IntroductionThis document defines serialization of the W3C XQuery
1.0 and XPath
2.0 Data Model
1.1
3.0 (XDM),
which is the data model of at least ,
, and
, and any other specifications that reference it.
In this document, examples and material labeled as Note
are provided for
explanatory purposes and are not normative.
Serialization is the process of converting an instance of the
into a sequence of octets. Serialization is
well-defined for most data model instances.
TerminologyIn this specification,
where they appear in upper case,
the words "MUST", "MUST NOT",
"SHOULD", "SHOULD NOT", "MAY", "REQUIRED", and
"RECOMMENDED" are to be interpreted as described in
.
As is indicated in
, conformance criteria for serialization
are determined by other specifications that refer to this specification.
A serializer is software that implements some or all of the
requirements of this specification in accordance with such conformance
criteria. A serializer is not REQUIRED to directly provide a
programming interface that permits a user to set serialization parameters
or to provide an input sequence for serialization.
In this document, material labeled
as "Note" and examples are provided for explanatory purposes and are not
normative.
Certain aspects of serialization are described in this specification as implementation-defined or implementation-dependent.
Implementation-defined indicates an
aspect that MAY differ between
serializers, but whose actual
behavior MUST be specified either by another specification that sets
conformance criteria for serialization (see )
or in documentation that accompanies the
serializer.
Implementation-dependent indicates an
aspect that MAY differ between
serializers, and whose actual
behavior is not REQUIRED to be specified either by another specification
that sets conformance criteria for serialization (see
) or in documentation that accompanies the
serializer.
In some instances, the
sequence that is input to serialization cannot be successfully converted
into a sequence of octets given the set of serialization parameter
() values specified. A
serialization error is said to occur in such an instance.
In some cases, a serializer is
REQUIRED to signal such an error.
What it means to signal a serialization error is determined by the
relevant conformance criteria () to which
the serializer conforms. In other cases,
there is an implementation-defined choice
between signaling a serialization error and performing a recovery action.
Such a recovery action will allow a
serializer to produce a sequence of
octets that might not fully reflect the usual requirements of the
parameter settings that are in effect.
Where this specification indicates that two strings are to be
compared without regard to case, the serializer
MUST translate any characters in the range
#x41 (LATIN CAPITAL LETTER A) to #x5A (LATIN CAPITAL LETTER Z),
inclusive, to the corresponding lower-case letters in the range
#x61 (LATIN SMALL LETTER A) to #x7A (LATIN SMALL LETTER Z) only
for the purposes of making the comparison. The comparison
succeeds if the two strings are the same length and the code
point of each character in the first string is equal to the
code point of the character in the corresponding position in
the second string.
Many terms used in this document are defined in the XPath specification
or the Data Model specification . Particular
attention is drawn to the following:
The term atomization is defined
in . It is a process that takes as input a sequence of nodes and atomic values, and
returns a sequence of atomic values, in which the nodes are replaced by their typed values as defined in
.
The term Node
is defined as part of .
There are seven kinds of nodes in the data model: document, element, attribute, text, namespace, processing instruction, and comment.
The term sequence
is defined in .
A sequence is an ordered collection of zero or more items.
The term
function item is defined in
.
The term string value
is defined in .
Every node has a string value. For example, the string value
of an element is the concatenation of the string values of all its descendant text nodes.
The term expanded QName
is defined in .
An expanded QName consists of an optional namespace URI and a local name. An expanded QName also retains its original namespace prefix (if any), to facilitate casting the expanded QName into a string.
An element or attribute that is in no namespace, or an expanded-QName whose namespace part is an empty sequence, is referred to as having a null namespace URI.
An element or attribute that does not have a null namespace URI, is referred to as having a non-null namespace URI.
A space character,
TAB character, CR character or NL character is referred to as a
whitespace character.
Where this specification indicates that an
XSLT instruction is evaluated, the behavior is as specified by
. Where it indicates that an XQuery expression is
evaluated, the behavior is as specified by .
NamespacesThis specification refers to several namespaces that affect the process
of serialization. These are:
the
Output declaration namespace,
http://www.w3.org/2010/xslt-xquery-serialization;
the
XML namespace,
http://www.w3.org/XML/1998/namespace;
the
XHTML namespace namespace,
http://www.w3.org/1999/xhtml;
the
SVG namespace,
http://www.w3.org/2000/svg; and
the
MathML namespace namespace,
http://www.w3.org/1998/Math/MathML.
Wherever an element node or attribute node is said to be in a
particular namespace, it is understood that the namespace URI of the
node is equal to the namespace URI corresponding to that namespace.
Wherever a namespace node is said to be a namespace node for a
particular namespace, it is understood that the
string value of the node is
equal to the namespace URI corresponding to that namespace.
Sequence NormalizationAn instance of the data model that is input to the serialization
process is a sequence.
Prior to serializing a sequence using any of
the output methods whose behavior is specified by this document
(),
the serializer MUST first
compute a normalized sequence for serialization; it
is the normalized sequence that is actually serialized.
The purpose of sequence normalization is
to create a sequence that can be serialized as a
well-formed XML document or external general parsed entity, that
also reflects the content of the input sequence to the extent possible.
The result of the sequence normalization process is a result tree.
The normalized sequence for serialization is constructed by applying all
of the following rules in order, with the initial sequence being
input to the first step, and the sequence that results from any
step being used as input to the subsequent step.
For any implementation-defined
output method, it is implementation-defined
whether this sequence normalization process takes place.
For any implementation-defined
output method, it is implementation-defined
whether sequence normalization
process takes place.Where the process of converting the input sequence
to a normalized sequence indicates that a value MUST be cast to
xs:string, that operation is
defined in of
.
Where a
step in the sequence normalization process indicates that a node should be
copied, the copy is performed in the same way as an XSLT
xsl:copy-of instruction that has a
validation attribute whose value is
preserve and has a
select attribute whose effective value is the
node, as described in
of ,
or equivalently in the same way as an XQuery
content expression as described in Step 1e of
of , where the construction mode is
preserve.
The steps in computing the normalized sequence are:
If the sequence that is input to serialization is
empty, create a sequence S1 that consists of a
zero-length string. Otherwise, copy each item in the sequence that is
input to serialization to create the new sequence S1.
For each item in S1, if the item is atomic, obtain the
lexical representation of the item by casting it to an xs:string
and copy the string representation to the new sequence; otherwise, copy the
item,
which will be a node,
to the new sequence.
The new sequence is S2.
If the item-separator serialization
parameter is absent, then for each subsequence of adjacent strings in
S2,
copy a single string to the new sequence equal to the values of the
strings in the subsequence concatenated in order, each separated by a
single space. Copy all other items to the new sequence.
Otherwise, copy each item in
S2 to the
new sequence, inserting between each pair of items a string whose
value is equal to the value of the item-separator
parameter.
The new sequence is S3.
For each item in S3, if the item is a string,
create a text node in the new sequence whose string value is equal to
the string; otherwise, copy the item to the new sequence. The new
sequence is S4.
For each item in S4, if the item is a document node,
copy its children to the new sequence; otherwise, copy the item to the new
sequence. The new sequence is S5.
For each subsequence of adjacent text nodes in S5, copy a single text node to the new sequence equal to the values of the text nodes in the subsequence concatenated in order. Any text nodes with values of zero length are dropped. Copy all other items to the new sequence. The new sequence is S6.
It is a serialization error if an item in S6 is an
attribute node,
a namespace node
or a
function item.
Otherwise, construct a new sequence,
S7, that consists of a single document node and
copy all the items in the sequence, which are all nodes, as children of
that document node.
S7 is the normalized sequence.
The result tree rooted at the document node that is
created by the final step of this sequence
normalization process is the
instance of the data model to which the rules of the appropriate
output method are applied. If the sequence
normalization process results
in a serialization error, the
serializer MUST signal the error.
If the item-separator
serialization parameter is absent, the sequence normalization process
for a sequence $seq is equivalent
to constructing a document node using the XSLT instruction:
<xsl:document>
<xsl:copy-of select="$seq" validation="preserve"/>
</xsl:document>or the XQuery expression:
declare construction preserve;
document {
for $s in $seq return
if ($s instance of document-node())
then $s/child::node()
else $s
}
declare construction preserve;
document { $seq }If the item-separator
serialization parameter is present, the sequence normalization process
for a sequence $seq is equivalent to constructing a
document node using the XSLT
instruction:
<xsl:document>
<xsl:for-each select="$seq">
<xsl:sequence select="if (position() gt 1) then $sep else ()"/>
<xsl:choose>
<xsl:when test=". instance of node()">
<xsl:sequence select="."/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="."/>
</xsl:otherwise>
</xsl:choose>
</xsl:for-each>
</xsl:document>or the XQuery expression:
declare construction preserve;
document {
for $item at $pos in $seq
let $node :=
if ($item instance of node()) then
$item
else
text { $item }
return
if ($pos eq 1) then
$node
else
($sep, $node)
}where the value of the sep
variable is a string whose value is equal to the value of the
item-separator serialization parameter.
This process results in a serialization error
if sequences contain
$seq contains functions,
attribute nodes or namespace
parentless attribute and/or
namespace
nodes.
Serialization ParametersThere are a number of parameters that influence how serialization
is performed. Host languages MAY allow users to specify any or all of these parameters, but
they are not REQUIRED to be able to do so. However, the host language
specification MUST specify how the values of all applicable parameters are to be
determined.
It is a serialization error if a parameter value is invalid for the given parameter. It
is the responsibility of the host language to specify how invalid values should be handled at the level of that language.
The following serialization parameters are defined:
| Serialization parameter name | Permitted values for parameter |
|---|
byte-order-mark | One of the enumerated values
yes or no. This parameter indicates
whether the serialized sequence of octets is to be preceded by
a Byte Order Mark. (See Section 5.1 of
.) The actual octet order used is
implementation-dependent.
If the encoding defines no Byte Order Mark, or if the Byte Order Mark is
prohibited for the specific Unicode encoding or implementation environment, then
this parameter is ignored. |
cdata-section-elements | A list of expanded QNames, possibly empty. |
doctype-public | A string of
PubidChar characters.
This parameter MAY be absent. |
doctype-system | A string of Unicode characters
that does not include both an
apostrophe (#x27) and a quotation mark (#x22) character.
This parameter MAY be absent. |
encoding | A string of Unicode characters in the range #x21 to #x7E (that is,
printable ASCII characters); the value SHOULD be a charset
registered with the Internet Assigned Numbers Authority
, or begin with the
characters x- or X-. |
escape-uri-attributes | One of the enumerated values yes or no. |
html-version | A decimal value. This parameter MAY be absent. |
include-content-type | One of the enumerated values yes or no. |
indent | One of the enumerated values yes or no. |
item-separator | A string of Unicode characters. This
parameter MAY be absent. |
media-type | A string of Unicode characters specifying the media type (MIME
content type) ;
the charset parameter of
the media type MUST NOT be specified explicitly in the value of
the media-type parameter.
If the destination of the serialized output
is annotated with a media type, this parameter MAY be used to
provide such an annotation. For example, it MAY be used to set
the media type in an HTTP header. |
method | An expanded QName with a null namespace URI, and the local part of
the name equal to one of xml, xhtml,
html or text, or having a non-null
namespace URI. If the namespace URI is non-null, the parameter
specifies an implementation-defined output method. |
normalization-form | One of the enumerated values NFC, NFD,
NFKC, NFKD, fully-normalized
or none, or an
implementation-defined value
of type
NMTOKEN. |
omit-xml-declaration | One of the enumerated values yes or no. |
standalone | One of the enumerated values yes, no or
omit. |
suppress-indentation | A list of expanded QNames, possibly empty. |
undeclare-prefixes | One of the enumerated values yes or no. |
use-character-maps | A list of pairs, possibly empty, with each pair consisting of
a single Unicode character and a string of Unicode characters. |
version | A string of Unicode characters. |
The octet order of the serialized result sequence of octects is
implementation-dependent.The value of the method parameter is an expanded QName.
If the value has a null namespace URI, then the local name identifies
a method specified in this document and MUST be one of xml, html,
xhtml, or text; in this case, the output method specified MUST be
used for serializing. If the namespace URI is non-null, then it identifies an
implementation-defined output method; the behavior in this case is not specified
by this document.
If the namespace URI is non-null for the method serialization
parameter, then the parameter specifies an implementation-defined
output method.In those cases where they have no important
effect on the content of the serialized result, details of the
output methods defined by this specification are left unspecified
and are regarded as implementation-dependent.
Whether a serializer uses
apostrophes or quotation marks to delimit attribute values in the
XML output method is an example of such a detail.
In those cases where they have no important
effect on the content of the serialized result, details of the
output methods defined by this specification are left unspecified
and are regarded as implementation-dependent.The detailed semantics of each parameter will be described
separately for each output method for which it is applicable. If the
semantics of a parameter are not described for an output method, then
it is not applicable to that output method.
Implementations MAY define additional serialization parameters, and MAY
allow users to do so. For this purpose, the name of a serialization
parameter is considered to be a QName; the parameters listed above are
QNames in no namespace, while any additional serialization parameters
that are either
implementation-defined or
defined by the host language
MUST have names that are namespace-qualified.
Any such
additional serialization parameters MUST NOT be in the namespace
http://www.w3.org/2010/xslt-xquery-serialization.
A host language MAY
specify the means by which an implementation can define such an additional
serialization parameter, and implementations MAY provide
mechanisms by which users can define such an additional serialization
parameter.
If the serialization method is one
of the four methods xml, html,
xhtml, or text, then the additional serialization parameters MAY
affect the output of the serializer to the extent (but only to the extent)
that this specification leaves the output implementation-defined or
implementation-dependent. For example, such parameters might control whether
namespace declarations on an element are written before or after the
attributes of the element, or they might define the number of space or tab
characters to be inserted when the indent parameter is set to yes; but they
could not instruct the serializer
to suppress the error that occurs when the
HTML output method encounters
illegal
characters
that are not permitted
(see error ).
The effect of additional serialization parameters on the output of the serializer,
where the name of such a parameter MUST be namespace-qualified, is
implementation-defined or implementation-dependent.
The extent of this effect on the output MUST NOT override the provisions of this specification.
Setting Serialization Parameters by Means of a Data Model InstanceA host language MAY provide, by reference to this
section, a mechanism by
which the settings of serialization parameters are supplied in the form of
an instance of the data model as specified in
. The instance of the data model used
to determine the settings of
serialization parameters MUST be processed as if by the
procedure described below.
With the exception of the use-character-maps parameter,
the setting of each serialization parameter
defined in this specification
is equal to the result of
evaluating the XQuery expression
(validate lax { document { . } })
/output:serialization-parameters
/output:*[local-name() eq $param-name]/data(@value)
or equivalently the XSLT instructions
<xsl:sequence>
<xsl:variable name="validated-instance">
<xsl:document validation="lax">
<xsl:sequence select="."/>
</xsl:document>
</xsl:variable>
<xsl:sequence select="$validated-instance
/output:serialization-parameters
/output:*[local-name() eq $param-name/data(@value)"/>
</xsl:sequence>
with the supplied instance of the data model as the context item, the
param-name variable having as its value a value of type
xs:string equal to
the local part of the name of the particular serialization parameter, and
the other components of the dynamic context and static context as
specified in the subsequent tables. If in any case evaluating this
expression would yield an error,
serialization error
results.
If the result of evaluating this expression for a particular serialization
parameter is the empty sequence:
if the parameter is either cdata-section-elements or
suppress-indentation and the result of evaluating
the XQuery expression
(validate lax { document { . } })
/output:serialization-parameters
/output:*[local-name() eq $param-name]
or equivalently the XSLT instructions
<xsl:sequence>
<xsl:variable name="validated-instance">
<xsl:document select="." validation="lax">
<xsl:sequence select="."/>
</xsl:document>
</xsl:variable>
<xsl:sequence select="$validated-instance
/output:serialization-parameters
/output:*[local-name() eq $param-name"/>
</xsl:sequence>
with the same settings of the static context and dynamic context is not an
empty sequence, the setting of the parameter is the empty list;
otherwise, the setting of the parameter is
unspecified
absent.
The components of the static context used in evaluating the XQuery
expressions or XSLT instructions
are as defined in the following table.
| Static Context Component | XQuery or XSLT | Setting |
|---|
| XPath 1.0 compatibility mode | Both | false |
| Statically known namespaces | XQuery | The pair
(output,http://www.w3.org/2010/xslt-xquery-serialization)
|
| XSLT | The pairs
(output,http://www.w3.org/2010/xslt-xquery-serialization),
(xslt,http://www.w3.org/1999/XSL/Transform)
|
| Default element/type namespace | Both | "none" |
| Default function namespace | Both | http://www.w3.org/2005/xpath-functions |
| In-scope schema types, In-scope element declarations,
Substitution groups, In-scope attribute declarations | Both | As defined by the schema for serialization parameters
()
and any additional implementation-defined
in-scope schema components
|
| In-scope variables | Both | {param-name} |
| Context item static type | Both | node() |
| Statically-known
function signatures | Both | {fn:data($arg as item()*) as xs:anyAtomicType*} |
| Statically known collations | Both | { (http://www.w3.org/2005/xpath-functions/collation/codepoint,
The Unicode codepoint collation ) }
|
| Default collation | Both | The Unicode codepoint collation |
| Construction mode | XQuery | strip |
| Ordering mode | XQuery | ordered |
| Default order for empty sequences | XQuery | least |
| Boundary space policy | XQuery | strip |
| Copy-namespaces mode | XQuery | (preserve,inherit) |
| Base URI | Both | Absent |
| Statically known documents | Both | None |
| Statically known collections | Both | None |
| Statically known default collection type | Both | node()* |
| Statically known decimal formats | Both | None |
| Set of named keys | XSLT | {} |
| Values of system
properties | XSLT | None |
| Set of available
instructions | XSLT | The set of all instructions defined
by |
Implementation-defined schema components
MAY be included in the set of schema components
that are used in evaluating an XQuery expression or XSLT instruction
in the process of using an XDM instance to determine the settings
serialization parameters.The remaining components of the dynamic context used in evaluating the
XQuery expressions
or XSLT instructions
in the preceding table are as defined in the following
table.
| Dynamic Context Component | XQuery or XSLT | Setting |
|---|
| Context position | Both | 1 |
| Context size | Both | 1 |
| Variable values | Both | The param-name variable has
a value of type xs:string equal the local part of the name
of the serialization parameter under consideration |
| Function implementations | Both | The implementation of fn:data |
| Current dateTime | Both | Absent |
| Implicit timezone | Both | Absent |
| Available documents | Both | None |
| Available collections | Both | None |
| Default collection | Both | None |
| Current template rule | XSLT | Absent |
| Current mode | XSLT | The default mode |
| Current group | XSLT | Absent |
| Current grouping key | XSLT | Absent |
| Current captured substrings | XSLT | The empty sequence |
| Output state | XSLT | Temporary output state |
In the case of the use-character-maps parameter, the
XQuery
expression
(validate lax { document { . } })
/output:serialization-parameters/output:use-character-maps
/output:character-map[@character eq $char]/string(@map-string)
or equivalently the XSLT instructions
<xsl:sequence>
<xsl:variable name="validated-instance">
<xsl:document validation="lax">
<xsl:sequence select="."/>
</xsl:document>
</xsl:variable>
<xsl:sequence select="$validated-instance
/output:serialization-parameters
/output:use-character-maps
/output:character-map[@character eq $char
/string(@map-string)"/>
</xsl:sequence>
is evaluated for each Unicode character that is permitted in an XML
document. The dynamic context and static context used to evaluate the
expression are as defined above, except that in-scope variables is the set
{char} and the value of the variable "char"
is a value of type xs:string
of length one whose value is the Unicode character under consideration. If
the result of evaluating the expression is not an empty sequence, the pair
consisting of the Unicode character and the result of evaluating the
expression is part of the list of pairs in the value of the
use-character-maps parameter. It is a
serialization error
if the result of evaluating this expression for any character is a
sequence of length greater than one.
Using the same settings of the components of the dynamic context and
static context,
serialization error
results if the result
of evaluating the following
XQuery expression is not true
— that is, if
the data model instance specifies more than one setting for any
particular serialization parameter.
(document { . })/output:serialization-parameters
/(count(distinct-values(*/node-name(.))) eq (count(*)))
or equivalently if the result of evaluating the following XSLT
instructions is not true.
<xsl:sequence>
<xsl:variable name="doc">
<xsl:document>
<xsl:sequence select="."/>
</xsl:document>
</xsl:variable>
<xsl:sequence
select="$doc/output:serialization-parameters
/(count(distinct-values(*/node-name(.))) eq (count(*)))"/>
</xsl:sequence>
The result of evaluating either
will be false if the data model instance
specifies more than one setting
supplies a value
for any particular serialization parameter
more than once, or will be the
empty sequence if the data model instance does not have as its root node
an element node or a document node with an element node child, where the
local part of the name of the element node is
serialization-parameters and the namespace URI is
http://www.w3.org/2010/xslt-xquery-serialization.
A serializer or implementation of a host language does not need to
be accompanied by an XQuery processor nor by a general-purpose schema
validator in order to meet the requirements of this section. It merely
needs to be capable of extracting values from an XDM instance that
conforms to the schema for serialization parameters, while checking that
the constraints implied by the schema and additional constraints implied
by the XQuery validate expression or explicitly stated in this section are
satisfied.
The host language MAY provide additional mechanisms for overriding the
values of any serialization parameters specified through the mechanism
defined in this section, as well as additional mechanisms for specifying
the values of any serialization parameters whose values
remain unspecified
are absent
after applying the mechanism defined in this section.
If the instance of the data model contains elements or attributes
that are in a namespace other than
http://www.w3.org/2010/xslt-xquery-serialization, the
implementation MAY interpret them to specify the
values of implementation-defined
serialization parameters in an
implementation-defined manner.
If an instance of the
data model used to determine the settings of serialization parameters
contains elements or attributes that are in a namespace other than
http://www.w3.org/2010/xslt-xquery-serialization, the
implementation MAY interpret them to specify the
values of implementation-defined
serialization parameters in an
implementation-defined manner.
The following XML document, if converted to a data model instance
and processed using the mechanism described in this section,
would specify the settings of the method, version
and indent serialization parameters with the values
xml, 1.0 and yes, respectively.
<output:serialization-parameters
xmlns:output="http://www.w3.org/2010/xslt-xquery-serialization">
<output:method value="xml"/>
<output:version value="1.0"/>
<output:indent value="yes"/>
</output:serialization-parameters>
The following document would specify the setting of the
cdata-section-elements serialization parameter with value the
pair of expanded QNames
(http://example.org/book/chapter,heading) and
(http://example.org/book,footnote)
<output:serialization-parameters
xmlns:output="http://www.w3.org/2010/xslt-xquery-serialization"
xmlns:book="http://example.org/book"
xmlns="http://example.org/book/chapter">
<output:cdata-section-elements value="heading book:footnote"/>
</output:serialization-parameters>
The following document would specify the value of the method
serialization parameter with the value html.
Notice that in this example, the default namespace declaration
in scope has no effect on the interpretation of the setting of the
method parameter.
<output:serialization-parameters
xmlns:output="http://www.w3.org/2010/xslt-xquery-serialization"
xmlns="http://example.org/ext">
<output:method value="html"/>
</output:serialization-parameters>
The following document would specify the value of the method
serialization parameter with value equal to the expanded QName
(http://example.org/ext, jsp), and the
use-character-maps parameter with value equal to the list of
pairs, («, <%), (», %>)
<output:serialization-parameters
xmlns:output="http://www.w3.org/2010/xslt-xquery-serialization"
xmlns:ext="http://example.org/ext">
<output:method value="ext:jsp"/>
<output:use-character-maps>
<output:character-map character="«" map-string="<%"/>
<output:character-map character="»" map-string="%>"/>
</output:use-character-maps>
</output:serialization-parameters>
Phases of SerializationSerialization comprises five phases of processing
(preceded optionally by the sequence normalization process
described in ).
For an
implementation-defined output method,
any of these phases MAY be skipped or MAY be performed in a different
order than is specified here.
For the output methods defined in this specification,
these phases are carried out sequentially as follows:
A meta element is added to the normalized sequence along with discarding an existing
meta element, as controlled by the include-content-type parameter for the XHTML and HTML output methods.
Markup generation produces the character representation of
those parts of the serialized result that describe the structure of the normalized
sequence. In the cases of the XML, HTML and XHTML
output methods, this phase produces the character representations of the following:
the document type declaration;
start tags and end tags (except for
attribute values, whose representation is produced by the character
expansion phase);
processing instructions; and
comments.
In the cases of the XML and XHTML output methods,
this phase also produces the following:
the XML or text declaration; and
empty element tags (except for the attribute
values);
In the case of the text output method,
this phase replaces the single
document node produced by sequence
normalization with a new document node that has exactly one child,
which is a text node. The string value of the new text node is the string value
of the document node that was produced by sequence normalization.
Character expansion
is concerned with the representation of characters appearing in text and attribute nodes
in the normalized sequence. For each text and attribute node, the following rules are applied in sequence.
If the node is an attribute that is a URI attribute value
and the escape-uri-attributes parameter is set to require escaping of URI attributes,
apply URI escaping as defined below,
and skip rules b-e. Otherwise, continue with rule b.
URI escaping consists of the following three steps applied in sequence to the content of
URI attribute values:
normalize to NFC using the method defined in
percent-encode any special characters in the URI using the method defined in
escape according to
HTML
rules any characters (such as
< and &) where HTML requires
the rules of the XML or HTML output
method, whichever is applicable, any characters that require
escaping, and any characters that cannot be represented in the
selected encoding.
For example, replace < with <.
(See also section )
The values of attributes listed in
are URI attribute values.
Attributes are not considered to be URI attributes simply because they are namespace declaration attributes or have the type annotation xs:anyURI.
If the node is a text node whose parent element is selected by the rules of the
cdata-section-elements parameter for the applicable output method,
create CDATA sections as described below, and skip rules c-e. Otherwise, continue with rule c.
Apply the following two processes in sequence to create CDATA sections
Unicode Normalization if requested by the normalization-form parameter.
apply changes as detailed in the description of the cdata-section-elements parameter for the applicable output method.
Apply character mapping as determined by the
use-character-maps parameter for the applicable output method.
For characters that were substituted by this process, skip rules d and e.
For the remaining characters that were not modified by character mapping, continue with rule d.
Apply Unicode Normalization if requested by the normalization-form parameter.
Unicode Normalization
is the process of removing alternate representations of equivalent sequences from textual data,
to convert the data into a form that can be binary-compared for equivalence, as specified in
.
For specific recommendations for character normalization on the World Wide Web,
see .
The meanings associated with the possible values of the normalization-form parameter
are defined in section .
Continue with step e.
Escape according to
XML or HTML rules, as determined by
the applicable output method,
the rules of the XML or HTML output
method, whichever is applicable,
any characters (such as < and &) where XML or HTML requires
escaping, and any characters that cannot be represented in the selected encoding.
For example, replace < with <.
(See also section ).
For characters such as > where XML defines a built-in entity but does not
require its use in all circumstances, it is implementation-dependent whether the character
is escaped.
Indentation, as controlled by
the indent parameter and the
suppress-indentation parameter, MAY
add or remove
whitespace according to the rules defined by the applicable output method.
Encoding, as controlled by the
encoding parameter, converts the character stream
produced by the previous phases into an octet stream.
Serialization is only defined in terms of encoding the result as a stream of octets.
However, a serializer MAY provide an option that allows the encoding phase to be skipped, so
that the result of serialization is a stream of Unicode characters.
The effect of any such option is implementation-defined,
and a serializer is not required to support such an option.
The effect of providing an option that allows the encoding phase to be skipped,
so that the result of serialization is a stream of Unicode characters, is implementation-defined.
The serializer is not required to support such an option.
The XML output method serializes the normalized sequence as an XML entity that
MUST satisfy the rules for either a well-formed XML document entity or a well-formed XML
external general parsed entity, or both.
A serialization error results if the
serializer
is unable to satisfy those rules,
except for content modified by the character expansion phase of serialization,
as described in .
The effects of the character expansion phase could result in the serialized output
being not well-formed, but will not result in a serialization error.
If a serialization error results, the
serializer MUST signal the error.
If the document node of the
normalized sequence has a single element
node child and no text node children,
then the serialized output
is a well-formed XML document entity, and the serialized output
MUST conform to the
appropriate version of the
XML Namespaces Recommendation
or .
If the normalized sequence does not take this form, then
the serialized output is a well-formed XML external general parsed entity,
which, when referenced within a trivial XML document wrapper
like this:
<?xml version="version"?>
<!DOCTYPE doc [
<!ENTITY e SYSTEM "entity-URI">
]>
<doc>&e;</doc>where entity-URI is a URI for the entity,
and the value of the version
pseudo-attribute is the value of the version
parameter, produces a
document which MUST itself be a
well-formed XML document conforming
to the
corresponding version of the
XML Namespaces Recommendation
or .
A reconstructed tree may be
constructed by parsing the XML document and converting it into an
instance of the data model as specified in
.
The result of serialization MUST be such that the reconstructed tree
is the same as the result tree except for the following permitted differences:
If the document was produced by adding a document wrapper, as
described above, then it will contain an extra doc
element as the document element.
The order of attribute and namespace nodes in the two trees MAY be
different.
The following properties of corresponding nodes
in the two trees MAY be different:
the base-uri property of document nodes and element nodes;
the document-uri and unparsed-entities properties of document
nodes;
the type-name and typed-value properties of element and attribute
nodes;
the nilled property of element nodes;
the content property of text nodes, due to the effect of the
indent and use-character-maps
parameters.
The reconstructed tree MAY contain additional attributes and text nodes resulting from the
expansion of default and fixed values in its DTD or schema;
also, in the presence of a DTD, non-CDATA attributes may lose whitespace
characters as a result of attribute value normalization.
The type annotations of the nodes in the two trees MAY be different.
Type annotations in a result tree are discarded when the tree is serialized.
Any new type annotations obtained by parsing the document will depend on whether the serialized XML document is assessed against a schema,
and this MAY result in type annotations that are different from
those in the original result tree.
In order to influence the type annotations in the
instance of the data model that would result from processing a serialized XML document,
the author of the XSLT stylesheet, XQuery expression or other process
might wish to create the instance of the data model that is input to the
serialization process so that it makes use of mechanisms provided by
, such as xsi:type and
xsi:schemaLocation attributes. The serialization process
will not automatically create such attributes in the serialized
document if those attributes were not part of the result tree that is
to be serialized.
Similarly, it is possible that an element node in
the instance of the data model that is to be serialized has the nilled
property with the value true, but no xsi:nil
attribute. The serialization process will not create such an attribute
in the serialized document simply to reflect the value of the property.
The value of the nilled property has no direct effect on
the serialized result.
Additional namespace nodes MAY be present
in the reconstructed tree if the serialization process
did not undeclare one or more namespaces,
as described in ,
and the starting instance of the data model contained an element node
with a namespace node that declared some prefix, but a child element
of that node did not have any namespace node that declared the same prefix.
The result tree MAY contain namespace nodes
that are not present in the reconstructed tree, as the process of creating an instance
of the data model MAY ignore namespace declarations in some circumstances.
See and
of
for additional information.
If the indent parameter has
the value yes,
additional text nodes consisting of
whitespace characters MAY be present in the reconstructed tree; and
text nodes in the result tree that contained only whitespace
characters MAY correspond to text nodes in the reconstructed tree that contain additional
whitespace characters that were not present in the result tree
See for more information on the
indent parameter.
Additional nodes MAY be present in the
reconstructed tree due to the effect of character mapping in the character expansion phase,
and the values of attribute nodes and text nodes in the
reconstructed tree MAY be different from those in the result tree, due to
the effects of URI expansion, character mapping
and Unicode Normalization in
the character expansion phase of serialization.
The use-character-maps parameter can
cause arbitrary characters to be inserted into the serialized XML document
in an unescaped form, including characters that would be considered to be
part of XML markup. Such characters could result in arbitrary new element
nodes, attribute nodes, and so on, in the reconstructed tree that results from
processing the serialized XML document.
A consequence of this rule is that certain characters
MUST be output as character
references, to ensure that they survive
the round trip through serialization and parsing.
Specifically, CR, NEL and LINE
SEPARATOR characters in text nodes MUST be output respectively as
"
", "…", and
"
", or their equivalents; while CR, NL, TAB, NEL and
LINE SEPARATOR characters in attribute nodes MUST be output respectively
as "
", "
", "	",
"…", and "
", or their equivalents.
In addition, the non-whitespace control characters
#x1 through #x1F and #x7F through #x9F in text nodes and attribute nodes MUST be
output as character references.
For example, an attribute with the value "x" followed by "y"
separated by a newline will result in the output
"x
y" (or with any equivalent character
reference). The XML output cannot be "x" followed by a literal newline
followed by a "y" because after parsing, the attribute value would be
"x y" as a consequence of the XML attribute normalization
rules.
XML 1.0 did not permit
an XML processor to normalize NEL or LINE SEPARATOR characters to a LINE FEED character. However, if
a document entity that specifies version 1.1 invokes an external general
parsed entity with no text declaration or a text declaration that specifies
version 1.0, the external parsed entity is processed according to the rules
of XML 1.1. For this reason, NEL and LINE SEPARATOR characters in text and
attribute nodes MUST always be escaped using character references,
regardless of the value of the version parameter.
XML 1.0 permitted control characters in the range #x7F through #x9F
to appear as literal characters in an XML document, but XML 1.1
requires such characters, other than NEL,
to be escaped as character references. An
external general parsed entity with no text declaration or a text
declaration that specifies a version pseudo-attribute with value
1.0 that is invoked by an XML 1.1 document entity
MUST
follow the rules of XML 1.1. Therefore, the non-whitespace control
characters in the ranges #x1 through #x1F and #x7F through #x9F
MUST
always be escaped, regardless of the value of the version parameter.
It is a serialization error to specify the doctype-system parameter, or to specify the standalone parameter with a value other than omit, if the
instance of the data model contains text nodes or multiple element nodes as children
of the root node. The
serializer
MUST either signal the error, or recover
by ignoring the request to output a document type declaration or
standalone parameter.
The Influence of Serialization Parameters upon the XML Output MethodXML Output Method: the version ParameterThe version parameter specifies the version of XML
and the version of Namespaces in XML to
be used for outputting the instance of the data model.
The version output in the XML declaration (if an XML declaration is not omitted)
MUST correspond to the version of XML that
the serializer
used for outputting the instance of the data model. The value of the
version parameter
MUST match the
VersionNum
production of the XML Recommendation or .
A serialization error results if the value of the version parameter specifies
a version of XML that is not supported by the serializer;
the serializer MUST
signal the error.
This document provides the normative
definition of serialization for the XML output method if the
version parameter has either the value 1.0 or
1.1. For
any other value of version parameter, the behavior is
implementation-defined.
In that case the implementation-defined
behavior MAY supersede all other requirements of
this recommendation.
If an implementation
supports a value of the version parameter for the XML or XHTML
output method for which this document does not provide a normative definition,
the behavior is
implementation-defined.If the serialized result would contain an
NCName that contains a character that is not
permitted by the version of Namespaces in XML specified by the
version parameter, a serialization error results.
The serializer MUST signal the error.
If the serialized result would contain a character
that is not permitted by the version of XML specified by the
version parameter, a serialization error results. The
serializer MUST signal the error.
For example, if the version
parameter has the value 1.0, and the instance of the data
model contains a non-whitespace control character in the range #x1 to
#x1F, a serialization error results.
If the version parameter has the value 1.1
and a comment node in the instance of the data model contains a
non-whitespace control character in the range #x1 to #x1F or a
control character other than NEL in the range #x7F to #x9F, a
serialization error results.
XML Output Method: the html-version ParameterThe html-version parameter is not applicable to the
XML output method. It is the responsibility of the
host language to specify
whether an error occurs if this parameter is specified in combination
with the XML output method, or if the parameter is simply dropped.
XML Output Method: the encoding ParameterThe encoding parameter specifies the
encoding to be used for outputting the instance of the data model.
Serializers
are REQUIRED to support values of UTF-8 and
UTF-16. A serialization error occurs if an output
encoding other than UTF-8 or UTF-16 is
requested and the serializer
does not support that encoding. The serializer
MUST signal the error, or recover by using
UTF-8 or UTF-16 instead.
The serializer
MUST NOT use an encoding whose name does not match the
EncName
production of the XML Recommendation .
When outputting a newline character in the instance of the data model, the
serializer is free to represent it using any character sequence
that will be normalized to a newline character by an XML parser,
unless a specific mapping for the newline character is
provided in a character map (see ).
When outputting any other character that is defined in the
selected encoding, the character
MUST be output
using the correct representation of that character in the selected encoding.
It is possible that the instance of the data model will contain a character that
cannot be represented in the encoding that the serializer
is using for output. In this case, if the character occurs in a context where XML
recognizes character references (that is, in the value of an attribute
node or text node), then the character MUST be output as a character
reference. A serialization error occurs if such a character appears in
a context where character references are not allowed (for example, if
the character occurs in the name of an element). The serializer
MUST signal the error.
For example,
if a text node contains the character LATIN SMALL LETTER E WITH ACUTE (#xE9),
and the value of the encoding parameter is
US-ASCII, the character MUST be serialized as a character
reference. If a comment node contains the same character, a
serialization error results.
XML Output Method: the indent and suppress-indentation ParametersIf the indent parameter has the value
yes, then the XML output method MAY output
whitespace in addition to the whitespace in the instance of the data model
in order to indent the result so that a person will find it easier to read; if the
indent parameter has the value no, it
MUST NOT output any additional whitespace.
If the XML
output method does output additional whitespace, it
MUST use an
algorithm to output additional whitespace that satisfies all of the
following constraints:
The indent and
suppress-indentation parameters control whether the
serializer MAY adjust the whitespace
in the serialized result so that a person will find it easier to read.
If the indent parameter has the value yes,
the serializer MAY output whitespace characters in
addition to the whitespace characters in the instance of the data
model. It MAY also elide from the output whitespace
characters that occurred in the instance of the data model or replace
such whitespace characters with other whitespace characters.
The term content has the
same meaning as the term
defined in of
.
The immediate content of an element is the part of the
content of the element that is not
also in the content of a child element
of that element.
If the
indent parameter has the value no, the
serializer MUST NOT output any additional, elide
or replace whitespace characters. If the indent parameter
has the value yes, the serializer MUST
use an algorithm for dealing with whitespace characters that satisfies
all of the following constraints.
If more than one constraint applies,
the serializer
MUST apply the most restrictive constraint. That is, if
any applicable constraint indicates that whitespace
MUST NOT be added, elided or replaced, that
constraint prevails; if an applicable constraint indicates that
whitespace SHOULD NOT be added, elided or replaced,
while all other applicable constraints indicate that whitespace
MAY
be added, elided or replaced, whitespace SHOULD NOT
be added, elided or replaced.
Whitespace characters
MUST NOT
MAY
be added adjacent to a text node
that contains
non-whitespace charactersonly
if the text node contains only whitespace characters. Whitespace characters in
such a text node MAY also be elided or replaced.
For example, a tab MAY be inserted as a
replacement for existing spaces.
Whitespace characters
MUST NOT be added other than adjacent to an element
node, that is, immediately before a
start tag or immediately after an end
tag.
Whitespace characters
MUST NOT be added other than adjacent to an element,
comment or processing instruction node
— that is, immediately before a start tag, an empty element tag,
a comment or a processing instruction, or immediately after an end tag,
an empty element tag, a comment or a processing instruction.
Whitespace characters
MAY be added, elided or replaced in the
immediate content of an
element whose type annotation is xs:untyped or
xs:anyType and that has element node children, in the
immediate content of an element whose content model
is element only, or outside
the content of any element.
Whitespace characters
MUST NOT be added,
elided or replaced
in the immediate content of an element
whose content model is not known
to be element only other than
adjacent to an element node child of that element
known to be simple or
empty.
Whitespace characters
SHOULD NOT be added,
elided or replaced
in places where the characters would
constitute significant whitespace, for example, in the
immediate content of an element
that is annotated with a type
other than xs:untyped or xs:anyType, and
whose content model is known to be mixed.
Whitespace characters
MUST NOT be added,
elided or replaced
in the content
of an element
whose expanded QName is a member of the list of expanded QNames in the
value of the suppress-indentation parameter.
Whitespace characters MUST NOT be
inserted
added, elided or replaced
in a part of the result document that is controlled by an
xml:space attribute with value preserve.
(See for more information about the
xml:space attribute.)
In any location where the above rules allow
the addition of whitespace characters, existing whitespace characters
MAY also be removed or replaced.
For example, a tab MAY be inserted as a replacement
for existing spaces.
The effect of these rules is to ensure that whitespace is only
added in places where (a) XSLT's <xsl:strip-space>
declaration could cause it to be removed, and
(b) it does not affect the string value of any element node with
simple content. It is usually not safe to indent document types that include elements
with mixed content.
The whitespace added may possibly
be based on whitespace stripped from either the source document or the
stylesheet (in the case of XSLT), or
guided by other means that might depend on the host language,
in the case of an instance of the data model created using some other process.
XML Output Method: the cdata-section-elements ParameterThe cdata-section-elements parameter contains a list
of expanded QNames. If the expanded QName of the parent of a text node
is a member of the list, then the text node
MUST be output as a
CDATA section, except in those circumstances
described below.
If the text node contains the sequence of characters
]]>, then the currently open CDATA section
MUST be
closed following the ]] and a new CDATA section opened
before the >.
If the text node contains characters that are not
representable in the character encoding being used to output the
instance of the data model, then the currently open CDATA section
MUST be closed
before such characters, the characters
MUST be output using
character references or entity references, and a new CDATA
section
MUST be opened for any further
characters in the text node.
CDATA sections
MUST NOT be used except where they
have been explicitly requested by the user, either by using the
cdata-section-elements parameter, or by using some other
implementation-defined mechanism.
This is phrased to permit an implementor to provide an option that
attempts to preserve CDATA sections present in the source
document.
A serializer MAY provide an implementation-defined mechanism to place CDATA sections in the result tree.XML Output Method: the omit-xml-declaration and standalone ParametersThe XML output method
MUST output an XML declaration if the omit-xml-declaration parameter has the value no.
The XML declaration MUST include both version information and an encoding declaration.
If the standalone parameter has the value yes or the value no,
the XML declaration MUST include a standalone document declaration with the same value as the value of the standalone parameter.
If the standalone parameter has
the value omit, the XML declaration
MUST NOT include a standalone document declaration; this ensures
that it is both an XML declaration (allowed at the beginning of a
document entity) and a text declaration (allowed at the beginning of
an external general parsed entity).
A serialization error results if the
omit-xml-declaration parameter has the value
yes, and
the standalone parameter has a value other than
omit; or
the version parameter has a value other than
1.0 and the doctype-system
parameter is specified.
Otherwise, if the
omit-xml-declaration parameter has the value
yes, the XML output method
MUST NOT output an XML declaration.
XML Output Method: the doctype-system and doctype-public ParametersIf the doctype-system parameter is specified, the
XML output method
MUST output a document type
declaration immediately before the first element. The name following
<!DOCTYPE
MUST be the name of the first element,
if any. If the doctype-public parameter is also specified, then the
XML output method MUST output PUBLIC
followed by the public identifier and then the system identifier;
otherwise, it MUST output SYSTEM
followed by the system
identifier. The internal subset
MUST be empty. The
doctype-public parameter
MUST be ignored unless the
doctype-system parameter is specified.
XML Output Method: the undeclare-prefixes ParameterThe Data Model allows an element
node that binds a non-empty prefix to
have a child element node that does
not bind that same prefix. In Namespaces in XML 1.1 (), this can be represented accurately by undeclaring
prefixes. For the undeclaring prefix of the child element node,
if the undeclare-prefixes parameter has the value
yes, the output method is XML or XHTML, and the version
parameter value is greater than 1.0,
the serializer
MUST undeclare its namespace. If the
undeclare-prefixes parameter has the value no and the output method is XML or
XHTML, then the undeclaration of prefixes MUST NOT occur.
Consider an element x:foo with four in-scope namespaces
that associate prefixes with URIs as follows:
x is associated with
http://example.org/x
y is associated with
http://example.org/y
z is associated with
http://example.org/z
xml is associated with
http://www.w3.org/XML/1998/namespace
Suppose that it has a child element x:bar with three in-scope namespaces:
x is associated with
http://example.org/x
y is associated with
http://example.org/y
xml is associated with
http://www.w3.org/XML/1998/namespace
If namespace undeclaration is in effect, it will be serialized this way:
<x:foo xmlns:x="http://example.org/x"
xmlns:y="http://example.org/y"
xmlns:z="http://example.org/z">
<x:bar xmlns:z="">...</x:bar>
</x:foo>In Namespaces in XML 1.0 (), prefix undeclaration is not possible.
If the output method is XML or XHTML, the value of the undeclare-prefixes parameter is yes,
and the value of the version parameter is 1.0,
a serialization error results; the
serializer MUST signal the error.
XML Output Method: the normalization-form ParameterThe normalization-form parameter is applicable to the XML output method.
The values NFC and none MUST be supported by the serializer.
A serialization error results if the value of the
normalization-form parameter specifies a normalization form
that is not supported by the
serializer; the
serializer MUST signal the error.
The meanings associated with the possible values of
the normalization-form parameter are as follows:
NFC specifies the serialized result will be
in Normalization Form C, using the rules specified in .
NFD specifies the serialized result will be
in Normalization Form D, as specified in .
NFKC specifies the serialized result will be
in Normalization Form KC, as specified in .
NFKD specifies the serialized result will be
in Normalization Form KD, as specified in .
fully-normalized specifies the serialized result
will be in fully normalized text, as specified in .
none specifies that no Unicode Normalization will
be applied.
An implementation-defined value
has an implementation-defined
effect.
If the value of the normalization-form form parameter is not NFC, NFD,
NFKC, NFKD, fully-normalized,
or none then the meaning of the value and its effect is
implementation-defined.
If the value of the parameter is fully-normalized, then no
relevant construct of the parsed entity created by the serializer
may start with a composing character. The term relevant construct
has the meaning defined in section 2.13 of . If this condition is not
satisfied, a serialization error MUST be signaled.
Specifying fully-normalized as the value of this parameter
does not guarantee that the XML document output by the serializer will in fact
be fully normalized as defined in . This is because the serializer does
not check that the text is include normalized, which would involve
checking all external entities that it refers to (such as an external DTD).
Furthermore, the serializer does not check whether any character escape
generated using character maps represents a composing character.
XML Output Method: the media-type ParameterThe media-type parameter is applicable to the
XML output method.
See for more
information.
XML Output Method: the use-character-maps ParameterThe use-character-maps parameter is applicable to the XML output method.
The result of serialization using the XML output method is not
guaranteed to be well-formed XML if character maps have been specified.
See for more information.
XML Output Method: the byte-order-mark ParameterThe byte-order-mark parameter is
applicable to the XML output method. See
for more information.
The byte order mark may be undesirable under certain circumstances;
for example, to concatenate resulting XML fragments without additional processing to remove the byte order mark.
Therefore this specification does not mandate the byte-order-mark parameter to have the value yes when the encoding is UTF-16,
even though the XML 1.0 and XML 1.1 specifications state that entities encoded in UTF-16 MUST begin with a byte order mark.
Consequently, this specification does not guarantee that the resulting XML fragment,
without a byte order mark, will not cause an error when processed by a conforming XML processor.
XML Output Method: the escape-uri-attributes ParameterThe escape-uri-attributes parameter is
not applicable to the XML output method. It
is the responsibility of the host language to specify whether an error occurs if this parameter is specified in combination with the XML output method, or if the parameter is simply dropped.
XML Output Method: the include-content-type ParameterThe include-content-type parameter is
not applicable to the XML output method. It
is the responsibility of the host language to specify whether an error occurs if this parameter is specified in combination with the XML output method, or if the parameter is simply dropped.
XML Output Method: the item-separator ParameterThe effect of the item-separator serialization parameter
is described in .
XHTML Output MethodThe XHTML output method serializes the instance of the
data model as
XML, using the HTML compatibility guidelines defined in the XHTML
specification
(
or the XHTML syntax of HTML5
(see ).
An element node is recognized as an
HTML element by the XHTML output method if
the element node is in the
XHTML namespace,
regardless of the value of the
html-version
serialization parameter
or if the html-version
serialization parameter is absent; or
the value of the
html-version
serialization parameter is
5.0, the element has a
null namespace URI, and
the local part of the name is equal
to the name of an element defined by HTML5 ,
making the comparison
without regard to case.
It is entirely the responsibility of the
person or process that creates the instance of
the data model
to ensure that the instance of the data model
conforms to the or
specification
if the html-version
serialization parameter is absent or has a value less than
5.0
or the XHTML syntax of
HTML5 if the value of the
html-version serialization parameter is 5.0.
It is not an error if the
instance of the data model is invalid XHTML. Equally, it is entirely under the
control of the person or process that creates the instance
of the data model whether the output conforms to XHTML 1.0
Strict, XHTML 1.0 Transitional,
the XHTML syntax of HTML5 (see
),
or any other specific definition of XHTML.
The serialization of the instance of the data model follows the same rules as for
the XML output method, with the general exceptions noted below and parameter-specific exceptions in .
These differences are based on the HTML compatibility guidelines
published in Appendix C of
and on ,
both of which are designed
to ensure that as far as possible, XHTML is rendered correctly on user
agents designed originally to handle HTML.
The following XHTML elements have an EMPTY content model: area, base, br, col, embed, hr, img, input, link, meta, basefont, frame, isindex, and param.
The
void elements of HTML5 are
area, base,
br, col, command, embed,
hr, img, input,
keygen, link, meta,
param, source, track and
wbr.
If an element node that has no
child nodes is
recognized as an HTML element,
and
the
html-version
serialization parameter is
absent or has a value
less than 5.0, and the
content model of the HTML element
is not EMPTY
(for example, an empty title or paragraph); or
the value of the
html-version
serialization parameter is 5.0, and the
HTML element is not a void element,
the serializer
MUST NOT use the minimized form.
That is, it
MUST
output <p></p> and not
<p />.
If an element that has no
children is an XHTML
element
recognized as an HTML element,
and
with an
EMPTY content model,
the
html-version
serialization parameter is
absent or has a value
less than 5.0, and the
content model of the HTML element
is EMPTY
(for example, an empty
br or img element);
or
the value of the
html-version
serialization parameter is 5.0, and the
HTML element is
a void element,
the serializer
MUST use the minimized tag syntax,
for example
<br />, as the alternative syntax
<br></br> allowed by XML gives uncertain
results in many
existing
legacy
user agents.
If the
html-version
serialization parameter is
absent or has a value
less than 5.0,
the serializer
MUST include a
space before the trailing />, e.g.
<br />, <hr /> and
<img src="karen.jpg" alt="Karen" />.
If the
html-version
serialization parameter is
absent or has a value
less than 5.0,
the serializer
MUST NOT use the entity reference
' which, although
legal
defined
in XML and therefore in
XHTML, is not defined in
versions of HTML
prior to HTML5,
and is not recognized by all HTML user
agents.
If the value of the
html-version serialization parameter is 5.0,
any element node that has a prefix and is in the
XHTML namespace,
MathML namespace,
or SVG namespace
MUST be serialized with an unprefixed
element name. The serializer
MUST serialize
a default namespace declaration for the namespace, unless a default
namespace declaration for the same namespace URI is already in scope
for the element in the serialized result. It is a
serialization error
if the element
node has a namespace node for the default namespace whose value is not
equal to the namespace URI of the element node. The
serializer
MUST NOT serialize a namespace declaration for the
namespace node declaring the element node's prefix, unless an attribute
of the element node has the same prefix.
If the
html-version
serialization parameter is
absent or has a value
less than
5.0,
the serializer SHOULD output namespace declarations
in a way that is consistent with the requirements of the XHTML DTD if this is
possible.
If the value of the
html-version
serialization parameter is
5.0,
the serializer SHOULD
output namespace declarations in a way that is consistent with the requirements
of
.
The XHTML 1.0 DTDs require the declaration
xmlns="http://www.w3.org/1999/xhtml"
to appear on the html element, and only on the html element.
The
specification
permits
namespace declarations
to appear in a conforming document, but there are restrictions on which
elements they can appear.
The serializer MUST output namespace declarations that are consistent with
the namespace nodes present in the result tree, but it MUST avoid outputting
redundant namespace declarations on elements where the DTD would make them invalid,
for versions prior to HTML5, or where they
are not permitted by
,
for serialization according to the syntax of HTML5.
If the html element is generated by an XSLT literal result element of
the form <html xmlns="http://www.w3.org/1999/xhtml"> ... </html>, or by an
XQuery direct element constructor of the same form, then the html element in
the result document will have a node name whose prefix is "", which will
satisfy the requirements of the DTD. In other cases the prefix assigned to
the element is implementation-dependent.
and Appendix C of
describes
a number of compatibility guidelines for users of XHTML who wish to
render their XHTML documents with HTML user agents. In some cases, such
as the guideline on the form empty elements
should take, only the
serialization process itself has the ability to follow the guideline. In
such cases, those guidelines are reflected in the requirements on the
serializer
described above.
In all other cases, the guidelines can be
adhered to by the instance of the data model that is input to the serialization
process. The guideline on the use of whitespace characters in attribute
values is one such example. Another example is that xml:lang="..." does not serialize to both xml:lang="..." and lang="..." as required by some legacy user agents. It is the responsibility of the person or
process that creates the instance of the data model that is input to the
serialization process to ensure it is created in a way that is consistent
with the guidelines. No serialization error results if the input instance
of the data model does not adhere to the guidelines.
The Influence of Serialization Parameters upon the XHTML Output MethodXHTML Output Method: the version
ParameterThe behavior for the version
parameter for the XHTML output method is described in
.
XHTML Output Method: the html-version ParameterThe html-version parameter specifies whether the XHTML
output method will produce a serialized document following rules that
are tailored to the requirements of the XHTML syntax of
or the requirements of and .
The differences are described in detail throughout
.
XHTML Output Method: the encoding ParameterThe behavior for encoding parameter for the XHTML output method is described in .
XHTML Output Method: the indent and suppress-indentation ParametersIf the indent parameter has the value yes, the
serializer MAY add or remove whitespace as it serializes the
result tree,
if it observes the following
constraints.
Whitespace MUST NOT be added other than before or
after an element, or adjacent to an existing whitespace character.
Whitespace MUST NOT be added or removed adjacent to
an inline element. The inline elements are those elements
in the XHTML namespace
recognized
as HTML elements that are
in the %inline category of any of the XHTML 1.0 DTD's, in the
%inline.class category of the XHTML 1.1 DTD,
those elements defined to be phrasing
elements in HTML5
and elements
in the XHTML namespace
recognized
as HTML elements
with local names ins and del if they are used as
inline elements (i.e., if they do not contain element children).
Whitespace MUST NOT be added or removed inside a
formatted element, the formatted elements being those
in the XHTML namespace
recognized
as HTML elements
with local names pre, script, style,
title, and
textarea.
Whitespace characters
MUST NOT be added in the content of an element
whose expanded QName matches a
member of the list of expanded QNames in the
value of the suppress-indentation parameter.
The expanded QName of an element node
is considered to match a member of the list of expanded QNames
if:
the two expanded QNames are equal;
the expanded QNames both have null
namespace URIs, and the local parts of the two QNames are
equal without regard to case; or
the value of the
html-version
serialization parameter is
5.0, the local parts of the two QNames are equal
without regard to case
and one QName has a null namespace
URI and the namespace URI of the other is equal to the
XHTML namespace URI.
The effect of the above constraints is to
ensure any insertion or deletion of whitespace would not affect how
a conforming
an
HTML user agent
that conforms to the specified version
of HTML
would render the output, assuming the serialized document does
not refer to any HTML style sheets.
The HTML definition of whitespace is different from the XML
definition: see section 9.1 of 4.01 specification.
XHTML Output Method: the cdata-section-elements ParameterThe behavior for cdata-section-elements parameter for the XHTML output method is described in .
XHTML Output Method: the omit-xml-declaration and standalone ParametersThe behavior for omit-xml-declaration and standalone parameters for the XHTML output method is described in .
As with the XML output method, the XHTML
output method specifies that an XML declaration will be output unless it is suppressed using
the omit-xml-declaration parameter. Appendix C.1 of
provides advice on the consequences of including,
or omitting, the XML declaration.
XHTML Output Method: the doctype-system and doctype-public ParametersIf the value of the
html-version
serialization parameter is 5.0, the
doctype-system serialization parameter is
absent,
the first element node child of
the document node that is to be serialized
is
recognized as an HTML
element, the local part of the QName of which is equal to
the string HTML,
without regard to case,
and any text node preceding that
element in document order contains only whitespace characters,
then
the XHTML output method MUST output a document type
declaration immediately before the first element, with no public or
system identifier. The name following <!DOCTYPE
MUST
be the same as the local part of the
name of the element.
Otherwise, the behavior for doctype-system and doctype-public parameters for the XHTML output method is described in .
XHTML Output Method: the undeclare-prefixes ParameterThe behavior for undeclare-prefixes parameter for the XHTML output method is described in .
XHTML Output Method: the normalization-form ParameterThe behavior for normalization-form parameter for the XHTML output method is described in .
XHTML Output Method: the media-type ParameterThe behavior for media-type parameter for the XHTML output method is described in .
XHTML Output Method: the use-character-maps ParameterThe behavior for use-character-maps parameter for the XHTML output method is described in .
XHTML Output Method: the byte-order-mark ParameterThe behavior for byte-order-mark parameter for the XHTML output method is described in .
XHTML Output Method: the escape-uri-attributes Parameter
If the escape-uri-attributes parameter has the value
yes, the XHTML output method
MUST apply URI escaping to
URI attribute values, except that relative URIs MUST NOT be absolutized.
This escaping is deliberately confined to non-ASCII characters,
because escaping of ASCII characters is not always appropriate, for
example when URIs or URI fragments are interpreted locally by the HTML
user agent. Even in the case of non-ASCII characters, escaping can
sometimes cause problems. More precise control of URI escaping is
therefore available by setting escape-uri-attributes to
no, and controlling the escaping of URIs by using methods defined in
and .
XHTML Output Method: the include-content-type ParameterIf the instance of the data model includes a head element
in the XHTML namespace
recognized as
an HTML element,
and the include-content-type parameter has the value
yes,
the XHTML output method
MUST
add a meta element as the first child element of the
head element, specifying the character encoding actually
used.
For example,
<head>
<meta http-equiv="Content-Type" content="text/html; charset=EUC-JP" />
...The content type SHOULD be set to the value given for the
media-type parameter.
It is recommended that the host language use as default
value for this parameter one of the MIME types () registered for
XHTML. Currently, these are text/html (registered by )
and application/xhtml+xml (registered by ). Note that
some user agents fail to recognize the charset parameter if the
content type is not text/html.
If a meta element has been added to the head element as described above,
then any existing meta element child of the head element having an
http-equiv attribute with the value "Content-Type",
making the comparison
without consideration of casing
and leading/trailing spaces,
without regard to case
after first stripping leading and trailing spaces from the value of
the attribute solely for the purposes of comparison,
MUST be discarded.
This process removes possible parameters in the attribute value. For example,
<meta http-equiv="Content-Type" content="text/html;version='3.0'" />in the data model instance would be replaced by,
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />XHTML Output Method: the item-separator ParameterThe effect of the item-separator serialization parameter
is described in .
HTML Output MethodThe HTML output method serializes the instance of the data model as
HTML.
For example, the following XSL stylesheet generates html output,
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" version="4.0"/>
<xsl:template match="/">
<html>
<xsl:apply-templates/>
</html>
</xsl:template>
...
</xsl:stylesheet>In the example, the version attribute of the xsl:output element indicates the version of the HTML Recommendation to which the serialized result is to conform.
It is entirely the responsibility of the person or process that creates the instance of the data model to ensure that the instance of the data model conforms to the HTML Recommendation . It is not an error if the instance of the data model is invalid HTML. Equally, it is entirely under the control of the person or process that creates the instance of the data model whether the output conforms to HTML.
If the result tree is valid HTML, the
serializer MUST serialize the result in a way that
conforms with the version of HTML specified by the
version
serialization parameter
requested HTML
version.
Markup for ElementsAs is described in detail below,
the HTML output method
will not
MUST NOT
output an element
differently from the XML output method unless the
expanded QName of the element has a
null namespace URI
element is to be
serialized as an HTML
element.
The
portion of the serialized document representing the result of serializing
an element
whose expanded QName does not have a
null namespace URI,
that is not to be
serialized as an HTML
element
is known as an
XML Island.
An element node is serialized as an
HTML element if
the expanded QName of the element has a
null namespace URI,
regardless of the value of the
requested HTML
version, or
the value of the
requested HTML
version
is 5.0 or
greater, and
the element node is in the
XHTML namespace.
If the expanded QName of the element has a
null namespace URI
element is to be
serialized as an HTML
element,
but the local part of the expanded QName is not recognized as the name
of an HTML element, the element
MUST be output in the same way as a
non-empty, inline element such as span. In particular:
If the
result tree contains namespace
nodes for namespaces other than the
XML namespace
Any namespace node in the result tree
for the XML namespace, is ignored
by the HTML output method.
In addition,
if the
requested HTML version
is 5.0, any element node that has a prefix and is in the
XHTML namespace,
MathML namespace,
or SVG namespace
MUST be serialized
with an unprefixed element name. The serializer MUST
serialize an attribute with the name xmlns whose value is
equal to the namespace URI of the element node, unless an ancestor
element in the serialized result already has an attribute named
xmlnswith the same value, and no interverning element
has an attribute named xmlns with a different value.
It is a serialization error
if the element
node has a namespace node for the default namespace whose value is not
equal to the namespace URI of the element node. The serializer
MUST NOT serialize a namespace declaration for the
namespace node declaring the element node's prefix, unless an attribute
of the element node has the same prefix.
For namespace nodes in the result tree
that are not ignored, the HTML output method
MUST represent these namespaces using
attributes named xmlns or xmlns:prefix
in the same way as the XML output method would represent them when the
version parameter is set to 1.0.
If the result tree contains elements or attributes whose names have a
non-null namespace URI, the HTML output method
MUST generate
namespace-prefixed QNames for these nodes in the same way as the XML output
method would do when the version parameter is set to 1.0.
Where special rules are defined later in this section for
serializing specific HTML elements and attributes, these rules
MUST NOT be
applied to an element that is not to be
serialized as an HTML
element
or an attribute whose name has
a non-null
namespace URI. However, the generic rules for the HTML output method
that apply to all elements and attributes, for example the rules for
escaping special characters in the text and the rules for indentation,
MUST be used also for namespaced elements and attributes.
When serializing an element whose name is not defined in the
HTML specification, but that is
in the null namespace
is to be
serialized as an HTML
element, the HTML output method
MUST
apply the same rules (for example, indentation rules) as
when serializing a span element. The descendants of such
an element
MUST be serialized as if they were descendants of a
span element.
When serializing an element whose name is in a non-null
namespace, the HTML output method
MUST apply the same rules (for
example, indentation rules) as when serializing a div
element. The descendants of such an element
MUST be serialized as if
they were descendants of a div element,
except for the influence
of the cdata-section-elements serialization parameter
on any text node children of the element.
The HTML output method
MUST NOT output an end-tag for an empty element
if the element type has an empty content model,
and the value of the
requested HTML
version
is less than 5.0, or the element is a void
element and the value of the
requested HTML
version
is 5.0.
For HTML 4.0, the
element types that have an empty content model are
area, base, basefont,
br, col,
embed,
frame,
hr, img, input,
isindex, link, meta and
param.
For HTML5, the void elements are
area, base,
br, col, command, embed,
hr, img, input,
keygen, link, meta,
param, source, track and
wbr. It is implementation-defined
whether the basefont, frame and isindex
elements, which are not part of HTML5 are considered to be void elements when
the
requested HTML
version
has the value 5.0.
For the HTML output method,
it is implementation-defined
whether the basefont, frame and isindex
elements, which are not part of HTML5 are considered to be void elements when
the requested HTML
version has the value 5.0.
For example, an element written as
<br/> or <br></br> in an
XSLT stylesheet
MUST be output as <br>.
The markup generation step of the
phases of serialization only creates
start tags and end tags for the HTML output method, never XML-style
empty element tags. As such, a serializer
MUST serialize an HTML
element that has no children, but whose content model is not empty,
using a pair of adjacent start and end element tags, or as a solitary
start tag if permitted by the context.
For any element node that is to be
serialized as an HTML
element,
the HTML output method
MUST
recognize the names of
HTML elements
compare the local part of the name of
the element node with the names of HTML elements
regardless of case.
making the comparison
without regard to case.
If the local part of the name of the
element node, compares equal to that of any HTML element, the element node
MUST be recognized as being that kind of HTML
element.
For example, elements named
br, BR or Br
MUST all be
recognized as the HTML br element and output without an
end-tag.
The HTML output method
MUST NOT perform escaping for
the content
any text node
descendant, nor for any attribute of an element node descendant,
of
the
a
script
and
or
style
elements
element.
For example, a script element
created by an XQuery direct element constructor or an XSLT
literal result element, such as:
<script>if (a < b) foo()</script>or
<script><![CDATA[if (a < b) foo()]]></script>
MUST be output as
<script>if (a < b) foo()</script>A common requirement is to output a script element
as shown in the example below:
<script type="application/ecmascript">
document.write ("<em>This won't work</em>")
</script>This is
illegal
invalid
HTML, for the reasons explained in section B.3.2 of
the 4.01 specification. Nevertheless, it is possible to output
this fragment, using either of the following constructs:
Firstly, by use of a script element
created by an XQuery direct element constructor or an
XSLT literal result element:
<script type="application/ecmascript">
document.write ("<em>This won't work</em>")
</script>Secondly, by constructing the markup from ordinary text characters:
<script type="application/ecmascript">
document.write ("<em>This won't work</em>")
</script>As the specification points out, the correct way to write this
is to use the escape conventions for the specific scripting language.
For JavaScript, it can be written as:
<script type="application/ecmascript">
document.write ("<em>This will work<\/em>")
</script>The 4.01 specification also shows examples of how to write
this in various other scripting languages. The escaping MUST be done
manually; it will not be done by the serializer.
Writing AttributesThe HTML output method
MUST NOT escape
"<" characters occurring in attribute values.
The HTML output method
MUST output boolean
attributes (that is attributes with only a single allowed value that
is equal to the name of the attribute
in minimized form.
A boolean attribute is an
attribute with only a single allowed value in any of the HTML DTDs
or that is specified to be a boolean
attribute by HTML5 (see ), where the
allowed value is equal without regard to case
to the name of the attribute.
The HTML output method MUST output any boolean attribute in minimized form if
and only if the value of the attribute node actually is equal to the name of
the attribute
making the comparison without regard to case.
For example, a start-tag created
using the following XQuery direct element constructor or XSLT
literal result element
<OPTION selected="selected">MUST be output as
<OPTION selected>The HTML output method
MUST NOT escape a
& character occurring in an attribute value
immediately followed by a { character (see Section
B.7.1 of the HTML Recommendation ).
For example, a start-tag created
using the following XQuery direct element constructor or XSLT
literal result element
<BODY bgcolor='&{{randomrbg}};'>
MUST be output as
<BODY bgcolor='&{randomrbg};'>See for additional directives on how attributes MAY be written.
Writing Character DataThe HTML output method MAY output a character using a
character entity reference in preference to using a numeric character
reference, if an entity is defined for the character in the version of
HTML that the output method is using. Entity references and character
references SHOULD be used only where the character is not present in
the selected encoding, or where the visual representation of the
character is unclear (as with , for
example).
When outputting a sequence of
whitespace characters in the
instance of the data model, within an element where
whitespace
is
characters are
treated normally
(but not in elements such as pre and
textarea), the HTML output method
MAY
represent it using any sequence of whitespace
characters that will be treated
in the same way by an HTML user agent. See section 3.5 of for some additional information on
handling of whitespace by an HTML user agent
for versions of HTML prior to HTML5,
and see the for information on the handling of whitespace
characters by an HTML5 user agent..
The terms space character
and white_space character defined in HTML5 do not match the definition of
whitespace character in this
specification.
Certain characters
specifically the control
characters #x7F-#x9F,
are
legal
permitted
in XML, but not in HTML
prior to HTML5
— for example,
the control characters #x7F-#x9F, are
legal
permitted
in both XML 1.0 and XML 1.1, and
the control characters #x1-#x8, #xB, #xC and #xE-#x1F are
legal
permitted
in XML 1.1, but
none of these is permitted in HTML
prior to HTML5
.
It is a
serialization error to use the HTML
output method if such characters
appear in the instance of the data model
and the value of the
requested HTML
version
is less than 5.0. The
serializer
MUST signal the error.
The HTML output method
MUST terminate processing
instructions with > rather than
?>. It is a serialization error to use the HTML output method when > appears within a processing instruction in the data model instance being serialized.
The Influence of Serialization Parameters upon the HTML Output MethodHTML Output Method: the version
and html-version
ParametersThe
html-version or the
version attribute
serialization parameter
indicates the version of the HTML
Recommendation
or
to which the serialized result is
to conform.
If the
html-version serialization parameter is not absent, the
requested HTML version is the value of the
html-version serialization parameter; otherwise, it is
the value of the version serialization
parameter.
If the serializer does
not support the version of HTML specified by
this parameter
the requested
HTML version, it
MUST signal a
serialization error .
This document provides the normative
definition of serialization for the HTML output method if the
version parameter
requested HTML version
has the lexical form of a value of type decimal whose value
is 1.0 or greater, but no greater than
4.01
5.0. For any other value of
version parameter, the behavior is
implementation-defined.
In that case the
implementation-defined
behavior MAY supersede all other requirements
of this recommendation.
If an implementation
supports a value of the version parameter for the HTML output
method for which this document does not provide a normative definition, the
behavior is implementation-defined.HTML Output Method: the encoding ParameterThe encoding parameter specifies the encoding to be used.
Serializers are
REQUIRED to support values of UTF-8 and
UTF-16. A serialization error occurs if an output
encoding other than UTF-8 or UTF-16 is
requested and the serializer
does not support that encoding. The serializer
MUST signal the error.
It is possible that the instance of the data model will contain a character that
cannot be represented in the encoding that the serializer
is using for
output. In this case, if the character occurs in a context where HTML
recognizes character references, then the character
MUST be output
as a character entity reference or decimal numeric character
reference; otherwise (for example, in a script or
style element or in a comment), the serializer
MUST
signal a serialization error .
See regarding how this parameter is used with the include-content-type parameter.
HTML Output Method: the indent and suppress-indentation ParametersIf the indent parameter has the value yes, then the
HTML output method MAY add or remove whitespace as it
serializes the result tree,
if it observes the following
constraints.
Whitespace MUST NOT be added other than before or
after an element, or adjacent to an existing whitespace character.
Whitespace MUST NOT be added or removed adjacent to
an inline element. The inline elements are those included in the
%inline category of any of the HTML 4.01 DTD's
or those elements defined to be phrasing
elements in HTML5, as well as the
ins and del elements if they are used as inline
elements (i.e., if they do not contain element children).
Whitespace MUST NOT be added or removed inside a
formatted element, the formatted elements being pre,
script, style,
title,
and textarea.
Whitespace characters
MUST NOT be added in the content of an element
whose expanded QName matches
a member of the list of expanded QNames in the
value of the suppress-indentation parameter.
The expanded QName of an element node
is considered to match a member of the list of expanded QNames
if:
the two expanded QNames are equal;
the expanded QNames both have null
namespace URIs, and the local parts of the two QNames are
equal without regard to case; or
the value of the
requested HTML
version
is 5.0, the local parts of the two QNames are equal
without regard to case
and one QName has a null namespace
URI and the namespace URI of the other is equal to the XHTML
namespace URI.
The effect of the above constraints is to
ensure any insertion or deletion of whitespace would not affect how an
conforming
HTML user agent would render the output, assuming the serialized document does
not refer to any HTML style sheets.
Note that the HTML definition of whitespace is different from the XML definition
(see section 9.1 of the specification).
HTML Output Method: the cdata-section-elements ParameterThe cdata-section-elements parameter is not applicable to the HTML output method, except in the case of XML Islands.
HTML Output Method: the omit-xml-declaration and standalone ParametersThe omit-xml-declaration and standalone parameters are not applicable to the HTML output method.
HTML Output Method: the doctype-system and doctype-public ParametersIf the doctype-public or doctype-system
parameters are specified, then the HTML output method MUST
output a document type declaration.
immediately before the first
element. The name following <!DOCTYPE
MUST be
HTML or html. If the
doctype-public parameter is specified, then the output
method
MUST output PUBLIC
followed by the specified
public identifier; if the doctype-system parameter is
also specified, it
MUST also output the specified
system identifier
following the public identifier. If the doctype-system
parameter is specified but the doctype-public parameter
is not specified, then the output method
MUST output
SYSTEM followed by the specified system identifier.
If the value of the
requested HTML
version
is 5.0, the
doctype-public and doctype-system serialization
parameters are both absent,
the first element node child of
the document node that is to be serialized
is to be
serialized as an HTML
element, the local part of the QName of which is equal to
the string HTML,
without regard to case,
and any text node that precedes that
element node in document contain only whitespace characters,
then
the HTML output method MUST output a document type
declaration, with no public or system identifier.
If the HTML output method MUST
output a document type declaration, it MUST be serialized
immediately before the first element, if any, and the name following
<!DOCTYPE MUST be HTML
or html.
HTML Output Method: the undeclare-prefixes ParameterThe undeclare-prefixes parameter is not applicable to the HTML output method.
HTML Output Method: the normalization-form ParameterThe
normalization-form
parameter is applicable to the
HTML output method.
The values NFC and
none MUST be supported by the serializer.
A serialization error results if the value of the normalization-form
parameter specifies a normalization form that is not supported by the
serializer;
the serializer
MUST signal the error.
HTML Output Method: the media-type ParameterThe media-type parameter is applicable to the
HTML output method.
See for more
information. See regarding how this parameter is used with the include-content-type parameter.
HTML Output Method: the use-character-maps ParameterThe use-character-maps parameter is applicable to the
HTML output method. See for more
information.
HTML Output Method: the byte-order-mark ParameterThe byte-order-mark parameter is
applicable to the HTML output method. See
for more information.
HTML Output Method: the escape-uri-attributes Parameter
If the escape-uri-attributes parameter
has the value yes,
the HTML output method MUST
apply URI escaping to
URI attribute values, except that relative URIs MUST NOT be absolutized.
This escaping is deliberately confined to non-ASCII characters,
because escaping of ASCII characters is not always appropriate, for
example when URIs or URI fragments are interpreted locally by the HTML
user agent. Even in the case of non-ASCII characters, escaping can
sometimes cause problems. More precise control of URI escaping is
therefore available by setting escape-uri-attributes to
no, and controlling the escaping of URIs by using methods defined in
and .
HTML Output Method: the include-content-type ParameterIf there is a head element,
and the include-content-type parameter
has the value yes,
the HTML output method
MUST add a meta element
as the first child element
of the head element specifying the character encoding
actually used.
For example,
<HEAD>
<META http-equiv="Content-Type" content="text/html; charset=EUC-JP">
...The content type MUST
be set to the value given for the
media-type parameter.
If a meta element has been added to the head element as described above,
then any existing meta element child of the head element having an
http-equiv attribute with the value
"Content-Type", making the comparison
without consideration of case and
leading or trailing spaces,
without regard to case
after first stripping leading and trailing spaces from the value of
the attribute solely for the purposes of comparison,
MUST be discarded.
This process removes possible parameters in the
attribute value. For example,
<meta http-equiv="Content-Type" content="text/html;version='3.0'"/>in the data model instance would be replaced by,
<meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>HTML Output Method: the item-separator ParameterThe effect of the item-separator serialization parameter
is described in .
Text Output MethodThe Text output method serializes the instance of the data model by
outputting the string value of the
document node created by
the markup generation step of the
phases of serialization without any
escaping.
A newline character in the instance of the data model MAY be output using any
character sequence that is conventionally used to represent a line
ending in the chosen system environment.
The Influence of Serialization Parameters upon the Text Output MethodText Output Method: the version ParameterThe version parameter is not applicable to the Text output method.
Text Output Method: the html-version ParameterThe html-version parameter is not applicable to the
Text output method.
Text Output Method: the encoding ParameterThe encoding parameter identifies the encoding that
the Text output method
MUST use to convert sequences of
characters to sequences of bytes.
Serializers
are REQUIRED to support values of UTF-8 and
UTF-16.
A serialization error
occurs if the serializer
does not support the encoding specified
by the encoding parameter.
The serializer
MUST signal the error.
If the instance of the data model contains a
character that cannot be represented in the encoding that the
serializer is using for output, the serializer
MUST
signal a serialization error .
Text Output Method: the indent and suppress-indentation ParametersThe indent
parameter is
and suppress-indentation
parameters are not applicable to the Text output method.
Text Output Method: the cdata-section-elements ParameterThe cdata-section-elements parameter is not applicable to the Text output method.
Text Output Method: the omit-xml-declaration and standalone ParametersThe omit-xml-declaration and standalone parameters are not applicable to the Text output method.
Text Output Method: the doctype-system and doctype-public ParametersThe doctype-system and doctype-public parameters are not applicable to the Text output method.
Text Output Method: the undeclare-prefixes ParameterThe undeclare-prefixes parameter is not applicable to the Text output method.
Text Output Method: the normalization-form ParameterThe normalization-form
parameter is applicable to the
Text output method.
The values NFC
and none MUST be supported by the serializer.
A serialization error results if the value of the
normalization-form parameter specifies a normalization form
that is not supported by the serializer; the
serializer MUST signal the
error.
Text Output Method: the media-type ParameterThe media-type parameter is applicable to the
Text output method.
See for more
information.
Text Output Method: the use-character-maps ParameterThe use-character-maps parameter is applicable to the
Text output method.
See for more
information.
Text Output Method: the byte-order-mark ParameterThe byte-order-mark parameter is
applicable to the Text output method. See
for more information.
Text Output Method: the escape-uri-attributes ParameterThe escape-uri-attributes parameter is not applicable to the Text output method.
Text Output Method: the include-content-type ParameterThe include-content-type parameter is not applicable to the Text output method.
Text Output Method: the item-separator ParameterThe effect of the item-separator serialization parameter
is described in .
Character MapsThe use-character-maps parameter is a list of characters
and corresponding string substitutions.
Character maps allow a specific character appearing in a text or
attribute node in the instance of the data model to be replaced with a specified
string of characters during serialization. The string that is
substituted is output "as is," and the serializer performs no checks
that the resulting document is well-formed. This mechanism can
therefore be used to introduce arbitrary markup in the serialized
output.
See
of for examples of using character mapping in
XSLT.
Character mapping is applied to the characters that actually appear
in a text or attribute node in the instance of the data model, before any other
serialization operations such as escaping or Unicode Normalization are
applied. If a character is mapped, then it is not subjected to XML or
HTML escaping, nor to Unicode Normalization. The string that is
substituted for a character is not validated or processed in any way
by the serializer, except for translation into the target encoding. In
particular, it is not subjected to XML or HTML escaping, it is not
subjected to Unicode Normalization, and it is not subjected to further
character mapping.
Character mapping is not applied to characters in text nodes whose
parent elements are listed in the cdata-section-elements
parameter,
nor to characters for which output escaping has
been disabled (disabling output escaping is an
feature),
nor to characters in attribute
values that are subject to URI escaping defined for the HTML and
XHTML output methods, unless URI escaping has been disabled using the
escape-uri-attributes parameter in the output
definition.
On serialization, occurrences of a character specified in the
use-character-maps in text nodes and attribute values
are replaced by the corresponding string from the use-character-maps
parameter.
Using a character map can result in non-well-formed documents
if the string contains XML-significant
characters. For example, it is possible to create documents containing
unmatched start and end tags, references to entities that are not
declared, or attributes that contain tags or unescaped quotation
marks.
If a character is mapped, then it is not subjected to XML or HTML escaping.
A serialization error occurs if character mapping causes the output
of a string containing a character that cannot be represented in the
encoding that the serializer
is using for output. The serializer
MUST signal the error.
ConformanceSerialization is intended primarily as a component
of a host language.
A host language is another
specification that includes, by reference, this specification and all of
its requirements. A host language might be a programming language
such as or , or it
might be an application programming interface (API) intended to be used by
programs written in some other high-level programming language. The use of
the term language is not intended to preclude the possibility that
this specification might be referenced outside the context of a
programming language specification.
Therefore, thisThis document
relies on specifications that use it to specify conformance criteria
for Serialization in their respective environments.
Specifications that set conformance criteria for their use of
Serialization MUST NOT change the semantic definitions of
Serialization as given in this specification, except by
subsetting and/or compatible extensions. It is the responsibility of the host language to specify how serialization errors
should
are to
be handled.
Certain facilities in this specification are described as producing
implementation-defined results. A
claim that asserts conformance with this specification MUST be accompanied by documentation
stating the effect of each implementation-defined feature. For convenience, a non-normative
checklist of implementation-defined features is provided at
.
ReferencesNormative References
Unicode
Character Encoding Model,
Unicode Consortium.
Unicode Standard Annex #17.
Unicode
Normalization Forms,
Unicode Consortium.
Unicode Standard Annex #15.
Informative References
XSLT 2.0 and XQuery 1.0 Serialization (Second Edition), W3C Recommendation, Henry Zongaro, Norman Walsh, Joanne Tong, et. al., Editors. World Wide Web Consortium, 14 December 2010. This version is http://www.w3.org/TR/2010/REC-xslt-xquery-serialization-20101214/Schema for Serialization ParametersThe following schema describes the structure of a Data Model instance
that can be used to specify the settings of serialization parameters using
the mechanism described in .
A copy of this schema is available at
http://www.w3.org/2013/01/xslt-xquery-serialization/schema-for-serialization-parameters.xsd.
Summary of Error ConditionsThis document uses the err prefix which represents the same namespace URI (http://www.w3.org/2005/xqt-errors) as defined in . Use of this namespace prefix binding in this document is not normative.
It is an error if an item in S6 in sequence normalization is an
attribute node or a namespace node.
It is an error if the
serializer
is unable to
satisfy the rules for
either a well-formed XML document entity or a well-formed XML
external general parsed entity, or both,
except for content modified by
the character expansion phase of serialization.
It is an error to specify the doctype-system parameter, or to specify the standalone parameter with a value other than omit, if the
instance of the data model contains text nodes or multiple element nodes as children
of the root node.
It is an error if the serialized result would contain an
NCName that contains a character that is not
permitted by the version of Namespaces in XML specified by the
version parameter.
It is an error if the serialized result would contain a character that is not
permitted by the version of XML specified by the version parameter.
It is an error if an output
encoding other than UTF-8 or UTF-16 is
requested and the serializer
does not support that encoding.
It is an error if a character that
cannot be represented in the encoding that the
serializer
is using for
output appears in
a context where character references are not allowed (for example if
the character occurs in the name of an element).
It is an error if the
omit-xml-declaration parameter has the value
yes, and
the standalone attribute has a value other than
omit; or the version parameter has a value other than
1.0 and the doctype-system
parameter is specified.
It is an error if the output method is xml or xhtml,
the value of the undeclare-prefixes
parameter is yes,
and the value of the version parameter is 1.0.
It is an error
if the value of the
normalization-form parameter specifies a normalization form
that is not supported by the
serializer.
It is an error if the value of the
normalization-form parameter is fully-normalized and any relevant construct
of the result begins with a combining character.
It is an error if the serializer
does not support the version of XML or HTML specified by the version parameter or the version of HTML specified by the
html-version or the version serialization parameter..
It is an error to use the HTML
output method if characters which are
legal
permitted
in XML but not in
the
requested HTML version
HTML, specifically the control
characters #x7F-#x9F,
appear in the instance of the data model.
It is an error to use the HTML output method when > appears within a processing instruction in the data model instance being serialized.
It is an error if a parameter value is invalid for the defined domain.
It is an error if evaluating an expression
in order to extract the setting of a serialization parameter from a data
model instance would yield an error.
It is an error if evaluating an expression
in order to extract the setting of the use-character-maps
serialization parameter from a data model instance would yield a
sequence of length greater than one.
It is an error if an instance of the data
model used to specify the settings of serialization parameters specifies
the value of the same parameter more than
once, or if the instance does not
have as its root node an element node or a document node with an element node
child, where the local part of the name of the element node is
serialization-parameters and the namespace URI is
http://www.w3.org/2010/xslt-xquery-serialization.
It is
an error if the XHTML or HTML output method attempts to serialize an
element node that has a prefix as an element with no prefix if that
element node has a namespace node for the default namespace whose value is
not equal to the namespace URI of the element node.
List of URI AttributesThe following list of attributes are declared as type %URI or
%UriList for a given HTML or XHTML element, with the exception of the
name attribute for element A which is not a URI type.
The name attribute for element A SHOULD be escaped as is
recommended by the HTML Recommendation in Appendix B.2.1.
| Attributes | Elements |
|---|
| action | FORM |
| archive | OBJECT |
| background | BODY |
| cite | BLOCKQUOTE, DEL, INS, Q |
| classid | OBJECT |
| codebase | APPLET, OBJECT |
| data | OBJECT |
| datasrc | BUTTON, DIV, INPUT, OBJECT, SELECT, SPAN, TABLE, TEXTAREA |
| for | SCRIPT |
| formaction | BUTTON, INPUT |
| href | A, AREA, BASE, LINK |
| icon | COMMAND |
| longdesc | FRAME, IFRAME, IMG |
| manifest | HTML |
| name | A |
| poster | VIDEO |
| profile | HEAD |
| src | AUDIO, EMBED, FRAME, IFRAME, IMG, INPUT, SCRIPT, SOURCE, TRACK, VIDEO |
| usemap | IMG, INPUT, OBJECT |
| value | INPUT |
Checklist of Implementation-Defined FeaturesThis appendix provides a summary of Serialization features whose effect is
explicitly implementation-defined.
The conformance rules (see ) require vendors to provide documentation
that explains how these choices have been exercised.
Change LogThis appendix details the changes that have been made since the publication of
the .
Changes applied for the current Public Working DraftThe following changes have been applied since the publication of the
fourth Public Working Draft to produce this, the fifth Public Working
Draft.
| Bugzilla bug (if applicable) | Erratum (if applicable) | Category | Description of change | Affected sections |
| Bugzilla bug 16311 | None | Substantive | Added new serialization parameter for specifying a separator that is
inserted between items in the sequence that is to be serialized. |
|
| None | None | Editorial | Added XSLT instructions equivalent to XQuery expressions for setting
serialization parameters by means of a data model instance, and other
editorial corrections and improvements. |
|
| None | None | Editorial | Clarified the definition of host language to make it clear that
APIs can be considered to be host languages. |
|
| Bugzilla 6129 | None | Substantive | Extended the definitions of the HTML and XHTML output methods to include
support for HTML5 serialization. |
|
| Bugzilla 17619 | None | Editorial | Text associated with links to the definitions of the terms NCName, EncName
and VersionNum was repeated several times. |
|
| Bugzilla 15915 | None | Editorial | Made uses of the terms "absent" and "unspecified" consistent. |
|
| Bugzilla 17282 | None | Substantive | Changed type of the normalization-form serialization
parameter to NMTOKEN. This would be an incompatible
change from XQuery 1.0, for any implementation that supported the
Serialization Feature, and supported an implementation-defined value
for the normalization-form serialization parameter that
did not have the lexical form of an NMToken. |
|
Changes applied for the
current
fourth
Public Working DraftThe following changes
have been
were
applied
since
following
the publication of the third Public Working Draft to produce the
current
fourth
Public Working Draft.
None of these changes introduces an incompatibility with
.
| Bugzilla bug (if applicable) | Erratum (if applicable) | Category | Description of change | Affected sections |
| Bugzilla
bug 12852 | None | Substantive | Corrected the type of the media-type serialization parameter
in the Schema for Serialization Parameters. |
|
| Bugzilla
bug 13688 | None | Substantive | Corrected the regular expression associated with the
encoding-string-type type in the Schema for Serialization
Parameters, so that hyphens are permitted to appear in the encoding
serialization parameter. |
|
| Bugzilla
bug 10176 | SE.E20 | Substantive | Clarified what it means for the html output method to output an XML island
as XML. |
|
| Bugzilla
bug 14751 | None | Editorial | Corrected typographical errors in the comments associated with the
yes-no-param-type and encoding-param-type types in
the Schema for Serialization Parameters. |
|
Changes applied for the third Public Working DraftThe following changes were applied
after the publication of the second Public Working Draft to produce
the third Public Working Draft.
None of these changes introduces an incompatibility with
, except as noted below.
| Bugzilla bug (if applicable) | Erratum (if applicable) | Category | Description of change | Affected sections |
| Bugzilla
bug 11635 | SE.E19 | Substantive | Clarified that serialization error SEPM0010 applies to the xhtml output
method as well as the xml output method. |
|
Changes applied for the second Public Working DraftThe following changes were applied
after the publication of the first Public Working Draft to produce
the second Public Working Draft.
None of these changes introduces an incompatibility with
, except as noted below.
| Bugzilla bug (if applicable) | Erratum (if applicable) | Category | Description of change | Affected sections |
| Bugzilla bug 6535 | None | Substantive | Added definition of the suppress-indentation serialization
parameter. |
|
| Bugzilla
bug 7829 | SE.E14 | Substantive | Clarified how minimized attributes are handled under the rules of the HTML
output method. |
|
| Bugzilla
bug 8245 | SE.E15 | Editorial | Corrected description of a serialization error that mentions which control
characters are not permitted under the rules of the HTML output method |
|
| Bugzilla
bug 7823 | SE.E16 | Substantive | Clarified how the script and style elements are
handled for the HTML output method. |
|
| Bugzilla
bug 8651 | SE.E17 | Substantive | Clarified what it means to compare without regard to case. |
|
| Bugzilla
bug 8206 | SE.E18 | Editorial | Clarified what it means to escape according to HTML or XML rules. |
|
| Bugzilla
bug 6808 | None | Substantive | Relaxed rules for the XML output method that specify where a serializer is
permitted to add whitespace. This introduces an incompatibility only inasmuch
as the serialized results produced by a serializer conforming to this
specification could differ from the results a serializer that adheres to
would be permitted to produce. |
|
| Bugzilla
bug 9302 | None | Substantive | Defined a mechanism for specifying serialization parameter settings in the
form of a data model instance. |
|
| None | None | Editorial | Replaced all uses of the words legal and illegal
with more appropriate terms. | |
Changes applied for the first Public Working DraftThe following changes were applied
after the publication of to produce
the first Public Working Draft.
None of these changes introduces an incompatibility with
.
| Bugzilla bug (if applicable) | Erratum (if applicable) | Category | Description of change | Affected sections |
| Bugzilla bug 6723 | SE.E13 | Substantive | Clarified how HTML elements that have no children but whose content model
is not empty are serialized. |
|
| Bugzilla
bug 6732 | SE.E12 | Substantive | Clarified for which versions of XML and HTML this document makes normative statements. |
|
| None | None | Substantive | Take into account presence of function items in a sequence that is to be serialized. |
|
| None | None | Editorial | Miscellaneous minor editorial corrections and improvements. | |