概述 root selector
示例
设置<html>背景颜色为黄色
$(":root").css("background-color","yellow");
显示根元素的标签名。
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>root demo</title>
<style>
span.fot {
color: red;
font-size: 120%;
font-style: italic;
}
</style>
<script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
<div id="log">The root of this document is: </div>
<script>
$( "<b></b>" ).html( $( ":root" )[ 0 ].nodeName ).appendTo( "#log" );
</script>
</body>
</html>
运行一下