html中全局遮罩

<!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>无标题文档</title>
<script type="text/javascript">
 function shade(){

  //获得ID为"a"的标签对象
  var aa = document.getElementById("a");

   //使aa使用.a的CSS样式
      aa.className = "a";
 }
</script>
<style type="text/css">
 html,body{
  /*清空html,body中的默认空白*/
  margin:0px;
  padding:0px;
 }
 .a{
  background-color:pink;
  width:100%;
  height:100%;
  position:absolute;/*绝对位子*/
  top:0px;
  left:0px;
  z-index:123;
                /*透明效果*/
  -moz-opacity:0.5;/*Firefox*/
  opacity:0.5;/*Opera*/
  filter:alpha(opacity=50); /*IE*/
 }
</style>
 
</head>
 
<body>
 
 <a href="javascript:shade()">遮罩</a>
 <a href="http://www.baidu.com">baidu</a>
 <div id="a"></div>
</body>
</html>

posted on 2012-08-06 21:24  Li-鹤鸣  阅读(384)  评论(0)    收藏  举报