tabindex - HTML: HyperText Markup Language 编辑

The tabindex global attribute indicates that its element can be focused, and where it participates in sequential keyboard navigation (usually with the Tab key, hence the name).

It accepts an integer as a value, with different results depending on the integer's value:

  • A negative value (usually tabindex="-1") means that the element is not reachable via sequential keyboard navigation, but could be focused with Javascript or visually by clicking with the mouse. It's mostly useful to create accessible widgets with JavaScript.

    A negative value is useful when you have off-screen content that appears on a specific event. The user won't be able to focus any element with a negative tabindex using the keyboard, but a script can do so by calling the focus() method.

  • tabindex="0" means that the element should be focusable in sequential keyboard navigation, after any positive tabindex values and its order is defined by the document's source order.
  • A positive value means the element should be focusable in sequential keyboard navigation, with its order defined by the value of the number. That is, tabindex="4" is focused before tabindex="5" and tabindex="0", but after tabindex="3". If multiple elements share the same positive tabindex value, their order relative to each other follows their position in the document source. The maximum value for tabindex is 32767. If not specified, it takes the default value 0.

    Avoid using tabindex values greater than 0. Doing so makes it difficult for people who rely on assistive technology to navigate and operate page content. Instead, write the document with the elements in a logical sequence.

If you set the tabindex attribute on a <div>, then its child content cannot be scrolled with the arrow keys unless you set tabindex on the content, too. Check out this fiddle to understand the scrolling effects of tabindex.

Accessibility concerns

Avoid using the tabindex attribute in conjunction with non-interactive content to make something intended to be interactive focusable by keyboard input. An example of this would be using a <div> element to describe a button, instead of the <button> element.

Interactive components authored using non-interactive elements are not listed in the accessibility tree. This prevents assistive technology from being able to navigate to and manipulate those components. The content should be semantically described using interactive elements (<a>, <button>, <details>, <input>, <select>, <textarea>, etc.) instead. These elements have built-in roles and states that communicate status to the accessibility that would otherwise have to be managed by ARIA.

Specifications

SpecificationStatusComment
HTML Living Standard
The definition of 'tabindex' in that specification.
Living StandardNo change from latest snapshot, HTML 5.1.
HTML 5.1
The definition of 'tabindex' in that specification.
RecommendationSnapshot of HTML Living Standard, no change from HTML5.
HTML5
The definition of 'tabindex' in that specification.
RecommendationSnapshot of HTML Living Standard. From HTML 4.01 Specification, the attribute is now supported on all elements (global attributes).
HTML 4.01 Specification
The definition of 'tabindex' in that specification.
RecommendationOnly supported on <a>, <area>, <button><input>, <object>, <select>, and <textarea>.

Browser compatibility

BCD tables only load in the browser

See also

如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。

扫码二维码加入Web技术交流群

发布评论

需要 登录 才能够评论, 你可以免费 注册 一个本站的账号。
列表为空,暂无数据

词条统计

浏览:105 次

字数:9288

最后编辑:6 年前

编辑次数:0 次

    我们使用 Cookies 和其他技术来定制您的体验包括您的登录状态等。通过阅读我们的 隐私政策 了解更多相关信息。 单击 接受 或继续使用网站,即表示您同意使用 Cookies 和您的相关数据。
    原文