javascript - How to check if a dom element is focusable?

Question

Many DOM elements are focusable: divs with tabIndex, input elements, etc. Is there any simple way to check whether an element is focusable than checking a zillion of different cases? Is there a jQuery method for this?

Answer 1

从这里回答“翻译”：哪些 HTML 元素可以接收焦点？

• <a>或<area>与href
• 任何未禁用的表单元素
• 内嵌框架
• 任何元素tabindex

另外，我相信隐藏的元素也无法获得焦点。

假设条件，以下函数可能会帮助您（假设它总是会收到一个 jQuery 元素）：

function canFocus( $el ) {
    if ( $el.is( ":hidden" ) || $el.is( ":disabled" ) ) {
        return false;
    }

    var tabIndex = +$el.attr( "tabindex" );
    tabIndex = isNaN( tabIndex ) ? -1 : tabIndex;
    return $el.is( ":input, a[href], area[href], iframe" ) || tabIndex > -1;
}