HTMLImageElement.longDesc

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过时
This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

obsolete property longDesc 在 HTMLImageElement interface specifies the URL of a text or HTML file which contains a long-form description of the image. This can be used to provide optional added details beyond the short description provided in the title 属性。

句法

descURL = htmlImageElement.longDesc;
htmlImageElement.longDesc = descURL;

值

A DOMString which may be either an empty string (indicating that no long description is available) or the URL of a file containing a long form description of the image's contents.

For example, if the image is a PNG of a flowchart. The longDesc property could be used to provide an explanation of the flow of control represented by the chart, using only text. This can be used by readers both as an explanation, but also as a substitute for visually-impaired users.

用法注意事项

此特性是 obsolete and should no longer be used. Instead of using longDesc to provide a link to a detailed description of an image, encapsulate the image within a link using the <a> 元素。

Consider the following older HTML:

<img src="taco-tuesday.jpg" longDesc="image-descriptions/taco-tuesday.html">

在这里， longDesc is used to indicate that the user should be able to access a detailed description of the image taco-tuesday.jpg in the HTML file image-descriptions/taco-tuesday.html .

This can be easily converted into modern HTML:

<a href="image-descriptions/taco-tuesday.html">
  <img src="taco-tuesday.jpg">
</a>

With that, the image is a link to the HTML file describing the image in more detail.

规范

规范	状态	注释
HTML 4.01 Specification The definition of 'HTMLImageElement.longDesc' in that specification.	推荐	Provides an actual description of this property; the HTML5 spec only says it's deprecated.

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`longDesc`	Chrome 1	Edge 12	Firefox Yes	IE ?	Opera Yes	Safari Yes	WebView Android Yes	Chrome Android Yes	Firefox Android Yes	Opera Android ?	Safari iOS Yes	Samsung Internet Android Yes

图例

完整支持
兼容性未知 ?

元数据

最后修改： Feb 22, 2020

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句法

值

用法注意事项

规范

浏览器兼容性

图例

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