| Alternative content type | (X)HTML 4.x | HTML5 | SVG |
|---|---|---|---|
| @alt for IMG | x | x | x |
| @alt for AREA | x | x | |
| @alt for INPUT type=image | x | x | |
| @alt for EMBED (delete this) | this does not exist in HTML4 though may be supported by UAs | (not mentioned in spec) | |
| @longdesc for IMG | x | pending | |
| @longdesc for FRAME | x | pending | |
| @longdesc for IFRAME | x | pending | |
| @summary for TABLE | x | x | |
| @abbr for TH | x | x | |
| @abbr for TD | x | (not in the spec) | |
| @title for A | x (this is advisory, should it really be alternative content?) | ||
| @title for ABBR | x | x | |
| @title for ACRONYM | x | deprecated | |
| @title for many other things | x - spec says 'advisory' | x | |
| @cite for Q ?? it is a URI | to me this is a source, much like for an image, could be made actionable by the UA, do we have an example? | x (there is a bugreport in html5 for this pending.) | |
| 'fallback content' for OBJECT | x | x | |
| 'fallback content' for EMBED | x (is not valid in HTML4, but still supported by browsers) | x | |
| 'fallback content' for CANVAS | x | ||
| 'fallback content' for IFRAME | x | x | |
| 'fallback content' for IMG | x | x | |
'fallback content' for MATH |
x | ||
'fallback content' for SVG |
x | ||
'fallback content' for AUDIO |
x | ||
| 'fallback content' for VIDEO | x | ||
| @srcdoc for IFRAME | |||
| DETAILS and SUMMARY elements | |||
| @title (hint) for COMMAND | |||
| NOFRAMES for FRAME | x | ||
| @title on INPUT type=radio | x | ||