<html>
<head>
<style>
#myDIV
{
border:1px solid black;
width:300px;
height:300px;
background:url('smiley.gif') no-repeat;
}
</style>
</head>
<body>
<p>点击“尝试一下”按钮扩大 DIV 元素的背景大小：</p>
<button onclick="myFunction()">尝试一下</button>
<div id="myDIV">
<h1>Hello</h1>
</div>
<script>
function myFunction()
{
document.getElementById("myDIV").style.backgroundSize = "60px 120px";
}
</script>
</body>
</html>