This is revision 1.5612.
Author requirements:
The width
and height
attributes on
img
, iframe
, embed
,
object
, video
, and, when their type
attribute is in the Image Button state,
input
elements may be specified to give the dimensions
of the visual content of the element (the width and height
respectively, relative to the nominal direction of the output
medium), in CSS pixels. The attributes, if specified, must have
values that are valid
non-negative integers.
The specified dimensions given may differ from the dimensions specified in the resource itself, since the resource may have a resolution that differs from the CSS pixel resolution. (On screens, CSS pixels have a resolution of 96ppi, but in general the CSS pixel resolution depends on the reading distance.) If both attributes are specified, then one of the following statements must be true:
The target ratio is the ratio of the
intrinsic width to the intrinsic height in the resource. The specified width and specified
height are the values of the width
and height
attributes respectively.
The two attributes must be omitted if the resource in question does not have both an intrinsic width and an intrinsic height.
If the two attributes are both zero, it indicates that the element is not intended for the user (e.g. it might be a part of a service to count page views).
The dimension attributes are not intended to be used to stretch the image.
User agent requirements: User agents are expected to use these attributes as hints for the rendering.
The width
and height
IDL attributes on
the iframe
, embed
, object
,
and video
elements must reflect the
respective content attributes of the same name.
For iframe
, embed
, and
object
the IDL attributes are DOMString
;
for video
the IDL attributes are unsigned
long
.
The corresponding IDL attributes for img
and input
elements are defined in those
respective elements' sections, as they are slightly more specific to
those elements' other behaviors.