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Links an image to a description of its content, for enhanced accessibility

Applies to dom/HTMLImageElement
## Examples

The description is somewhere on the same page as the image

<img src="" alt="Drinks are getting sweeter"
<p id="graph1Explained">A blue capital letter "W" with kerning so it touches a blue 3, followed by a black shadow of a white capital letter C all on a white background</p>

The description is one of several within an external page

<img src="ExampleImage" alt="example" longdesc=""/>

The description is included in a data: URI

<img src="logo" alt="W3C" longdesc="data:text/html;charset=utf-8;,%3C!DOCTYPE%20html%3E



The long description supplements the shorter description specified by the alt attribute. Windows Internet Explorer 8 or later. In IE8 Standards mode, the value of the longDesc attribute for the frame, iframe, and img elements depends on the context of the reference to the attribute. When read as a Document Object Model (DOM) attribute, longDesc returns an absolute URL. The value specified by the page author is returned when longDesc is read as a content attribute, when the page is displayed in an earlier document compatibility mode, or when the page is viewed with an earlier version of the browser. For more information, see Attribute Differences in Internet Explorer 8. The alt attribute is no longer displayed as the image tooltip for pages displayed in IE8 mode. The target of the longDesc attribute is now displayed as the tooltip, if present; otherwise, the title is displayed. However, the alt attribute is displayed as the Microsoft Active Accessibility (MSAA) tooltip. If this attribute is not present, the title attribute is displayed instead. For more information, see Accessibility section in What’s New in Internet Explorer 8. longDesc was introduced in Microsoft Internet Explorer 6.

Related specifications

HTML5 Image Description Extension
W3C Recommendation

See also

Other articles