HTML and MIME
The definition of the HTML content
subtype is
- MIME Type name
- text
- MIME subtype name:
- html
- Required parameters:
- none
- Optional parameters:
- level, version,
charset
Level
The level parameter specifies the
feature set which is used in the
document. The level is an integer
number, implying that any features
of same or lower level may be present
in the document. Levels are defined
by this specification.
Version
In order to help avoid future compatibility
problems, the version parameter may
be used to give the version number
of this specification to which the
document conforms. The version
number appears at the front of this
document and within public identifier
for the SGML DTD.
Character sets
The base character set (the SGML
BASESET) for HTML is ISO Latin-1.
This is the set referred to by any
numeric character references . The
actual character set used in the
representation of an HTML document
may be ISO Latin 1, or its 7-bit
subset which is ASCII. There is no
obligation for an HTML document to
contain any characters above decimal
127. It is possible that a transport
medium such as electronic mail imposes
constraints on the number of bits
in a representation of a document,
though the HTTP access protocol used
by W3 always allows 8 bit transfer.
When an HTML document is encoded
using 7-bit characters, then the
mechanisms of character references
and entity references may be used
to encode characters in the upper
half of the ISO Latin-1 set. In this
way, documents may be prepared which
are suitable for mailing through
7-bit limited systems.
Character set option (proposed)
The SGML declaration specified ISO
Latin 1 as the base character set.
The charset parameter is reserved
for future use. Its intended significance
is to override the base character
set of the SGML declaration. Support
of character sets other than ISO-Latin-1
is not a requirement for conformance
with this specification.