This is revision 1.5612.
output
elementfor
form
name
interface HTMLOutputElement : HTMLElement {
[PutForwards=value] readonly attribute DOMSettableTokenList htmlFor;
readonly attribute HTMLFormElement? form;
attribute DOMString name;
readonly attribute DOMString type;
attribute DOMString defaultValue;
attribute DOMString value;
readonly attribute boolean willValidate;
readonly attribute ValidityState validity;
readonly attribute DOMString validationMessage;
boolean checkValidity();
void setCustomValidity(DOMString error);
readonly attribute NodeList labels;
};
The output
element represents the result of a
calculation.
The for
content
attribute allows an explicit relationship to be made between the
result of a calculation and the elements that represent the values
that went into the calculation or that otherwise influenced the
calculation. The for
attribute,
if specified, must contain a string consisting of an unordered
set of unique space-separated tokens that are
case-sensitive, each of which must have the value of an
ID of an element in the same
Document
.
The form
attribute is used to
explicitly associate the output
element with its
form owner. The name
attribute represents the element's name.
The element has a value mode flag which is either value or default. Initially, the value mode flag must be set to default.
The element also has a default value. Initially, the default value must be the empty string.
When the value mode flag
is in mode default, the
contents of the element represent both the value of the element and
its default
value. When the value mode
flag is in mode value, the contents of the
element represent the value of the element only, and the default value is only
accessible using the defaultValue
IDL
attribute.
Whenever the element's descendants are changed in any way, if the
value mode flag is in mode
default, the element's
default value must
be set to the value of the element's textContent
IDL
attribute.
The reset
algorithm for output
elements is to set the
element's value mode flag
to default and then to
set the element's textContent
IDL attribute to the
value of the element's default value (thus
replacing the element's child nodes).
value
[ = value ]Returns the element's current value.
Can be set, to change the value.
defaultValue
[ = value ]Returns the element's current default value.
Can be set, to change the default value.
type
Returns the string "output
".
The value
IDL
attribute must act like the element's textContent
IDL
attribute, except that on setting, in addition, before the child
nodes are changed, the element's value mode flag must be set to value.
The defaultValue
IDL
attribute, on getting, must return the element's default value. On
setting, the attribute must set the element's default value, and, if
the element's value mode
flag is in the mode default, set the element's
textContent
IDL attribute as well.
The type
attribute must return the string "output
".
The htmlFor
IDL attribute must reflect the for
content attribute.
The willValidate
, validity
, and validationMessage
attributes, and the checkValidity()
and setCustomValidity()
methods, are part of the constraint validation API. The
labels
attribute provides a list
of the element's label
s. The form
and name
IDL attributes are part of the
element's forms API.
A simple calculator could use output
for its
display of calculated results:
<form onsubmit="return false" oninput="o.value = a.valueAsNumber + b.valueAsNumber"> <input name=a type=number step=any> + <input name=b type=number step=any> = <output name=o></output> </form>