<!DOCTYPE>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>hello world</title>
</head>
<body>
<div id="Layer1" style="position:absolute; width:100%; height:100%; z-index:-1">
<img src="pictures/background.jpg" height="100%" width="100%"/>
</div>
</body>
</html>
原文：http://www.cnblogs.com/waterair/p/6738822.html