:focus

示例

描述:

添加一个"focused"的类名给那些有focus方法的元素

css 代码:

.focused {
    background: #abcdef;
}

html 代码:

<div id="content">
    <input tabIndex="1">
    <input tabIndex="2">
    <select tabIndex="3">
        <option>select menu</option>
    </select>
    <div tabIndex="4">
        a div
    </div>
</div>

jQuery 代码:

$( "#content" ).delegate( "*", "focus blur", function( event ) {
    var elem = $( this );
    setTimeout(function() {
       elem.toggleClass( "focused", elem.is( ":focus" ) );
    }, 0);
});