菜鸟教程在线编辑器

 
                <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(runoob.com)</title>
</head>
<body>

<p>点击按钮计算 DIV 的背景颜色。</p>
<p><button onclick="myFunction()">点我</button></p>
<div id="test" style="height: 50px;background-color: rgb(178, 116, 230);">测试 DIV</div>
<p>计算值为: <span id="demo"></span></p>

<script>
function myFunction(){
    var elem = document.getElementById("test");
    var theCSSprop = window.getComputedStyle(elem, null).getPropertyValue("background-color");
    document.getElementById("demo").innerHTML = theCSSprop;
}
</script>

</body>
</html>
              