HTML Reference Manual

HTML tag大全

HTML: <img> longdesc attribute

The longdesc attribute specifies a hyperlink to the detailed description of the image.

Online examples

Several examples of how to use the longdesc attribute:

Example

<!DOCTYPE html>
<html>
<head>
<title>HTML:<img> longdesc attribute　-　基础教程网　oldtoolbag.com</title>
<body>
<!--　The description is on the same page as the image　-->
<img src="sun.gif" alt="oldtoolbag.com"　width="100"　height="132"　longdesc="#w3codebox_Explained">
<!--　The description is in an external page　-->
<img src="sun.gif" alt="oldtoolbag.com"　width="100"　height="132"　longdesc="w3codebox.txt">
<!--　The description is one of several within an external page　-->
<img src="sun.gif" alt="oldtoolbag.com"　width="100"　height="132"　longdesc="http://example.com/desc#item3">
<!--　The description is included in a data:URI　-->
<img src="sun.gif" alt="oldtoolbag.com"　width="100"　height="132"　longdesc="data:text/html;charset=utf-8;,%3C!DOCTYPE%20html%3E%3Chtml%3E%3Chead%3E%3Ctitle%3EDescription%20of%20the%20Logo%3C/title%3E%3C/head%3E%3Cbody%3E%3Cp%3ESome%20description%20goes%20here%3C/body%3E%3C/html%3E">
<div id="w3codebox_Explained">
　　<h2>Image sun.gif</h2>
　　<p>Description of the image.../p>
</div>
</body>
</html>

Test and see ‹/›

Browser Compatibility

IEFirefoxOperaChromeSafari

Almost all mainstream browsers do not support the longdesc attribute.

Definition and Usage

HTML5 The <img> longdesc attribute is not supported.

The longdesc attribute specifies a hyperlink to the detailed description of the image.

Tip:Since browsers have very poor support for the longdesc attribute, there is no need to use it. If you need to provide a long description for an image (if necessary), simply create a link to the description page (which is visible to anyone).

Syntax

<img longdesc="URL">

Attribute value

Value	Description
URL	Detailed description of the image linked by the hyperlink. Possible values: One ID for another element Absolute URL 　- Points to another website (such as LONGDESC = 'http:')//www.example.com/description.txt') Relative URL 　- Points to a file within a website (such as LONGDESC = 'description.txt')

　HTML <img> tag

HTML: <template> tag