css：滑动门

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>滑动门Demo</title>
<style type="text/css">
    .btn{height:28px; font-size:12px; text-decoration:none; line-height:28px;}
    .btn,.btn span{ float:left;background:url(btn.png) 0 0;  color:#fff;}
    .btn span{background-position: right 0;padding: 7px 8px 5px 0;margin: 0 0 0 8px;height: 16px;line-height: 16px;}
</style>
</head>

<body>
<a href="#" class="btn"><span>这是大按钮</span></a>
</body>
</html>
相当于a负责左门，span负责右门