<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<?php
$str = file_get_contents('http://cn.bing.com/HPImageArchive.aspx?idx=0&n=1');
if (preg_match("/<url>(.+?)</url>/ies", $str, $matches)) {
$imgurl = 'http://cn.bing.com' . $matches[1];
}
?>
<style type="text/css">
body {background-image: url("<?php echo $imgurl; ?>");}
</style>
</head>
<body>
</body>
</html>