Alt Text: Difference between revisions
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rm null text - purely decorative images should be included via CSS |
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#REDIRECT [[Alt attribute]] |
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[[Image:BBC.svg|thumb|right|Depending on where it appears, the alt text of the [[BBC]]'s logo might be "Corporate logo of the British Broadcasting Corporation", "BBC" or a null value. In this case, it's the full text of this caption.]] |
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[[Image:alt text.png|frame|right|Screenshot of preceding images' alt text (note "enlarge" option) rendered instead of the images.]] |
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'''Alt''' (or "''alternate''"/ "''alternative''") '''text''' is text included inside an <code>alt</code> attribute in [[HTML]] (et al.) documents which is to be [[rendering (computer graphics)|rendered]] when the [[HTML element|element]] it is applied to cannot be. |
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It is intended to be presented when the image (or other object) to which it pertains is not available to the user, for instance in a text-only [[web browser|browser]] or a [[refreshable Braille display]]. It is also available for indexing by [[search engine]]s. |
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In HTML 4.01, the presence of the attribute is a requirement with <code>img</code> and <code>area</code> elements, for [[World Wide Web Consortium|HTML standard]] compliance. It is optional for the <code>input</code> element and the [[deprecation|deprecated]] <code>[[applet]]</code> element. |
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Alt text may be null (<code>alt=""</code>); however, the use of ''meaningful'' alt text is necessary to comply with [[WAI|accessibility standards]] and is good practice. |
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Alt text is commonly, but incorrectly, refered to as an image's "alt tag". It is not intended to provide "pop up" text or [[tooltip]]s when a user's [[mouse (computing)|mouse]] hovers over the image, though alt text has historically been presented in this way in some [[web browser]]s; HTML's <code>title</code> attribute is intended for that purpose. |
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==External links== |
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*[http://www.w3.org/TR/html401/struct/objects.html#adef-alt W3C spec section on 'How to specify alternate text'] |
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*[http://ppewww.ph.gla.ac.uk/~flavell/alt/alt-text.html Alt text guidance from Alan Flavell] with section on humourous gaffes |
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*[http://diveintoaccessibility.org/day_23_providing_text_equivalents_for_images.html Dive in to accessibility page on alt text] |
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*[http://www.yourhtmlsource.com/accessibility/contentaccessibility.html Content Accessibility Tutorial] |
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*[http://www.cs.tut.fi/~jkorpela/html/alt.html Alt text guidelines from Jukka "Yucca" Korpela] |
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{{Web-stub}} |
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Latest revision as of 18:21, 18 June 2009
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