<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>jQuery 遮罩层</title><style type="text/css">/* 半透明的遮罩层 */#overlay { background: #000; filter: alpha(opacity=50); /* IE的透明度 */ opacity: 0.5; /* 透明度 */ display: none; position: absolute; top: 0px; left: 0px; width: 100%; height: 100%; z-index: 100; /* 此处的图层要大于页面 */ display:none; _ padding: 0px 0px 0px 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; border-left: 3px solid rgb(108, 226, 108); line-height: 20px; width: 640px; clear: both; border-radius: 0px !important; border-top: 0px !important; border-right: 0px !important; border-bottom: 0px !important; border-image: initial !important; bottom: auto !important; float: none !important; height: auto !important; left: auto !important; outline: 0px !important; overflow: visible !important; position: static !important; right: auto !important; top: auto !important; vertical-align: baseline !important; box-sizing: content-box !important; font-family: Consolas, "Bitstream Vera Sans Mono", "Courier New", Courier, monospace !important; min-height: auto !important; color: gray !important;">#a0a0a0; /* 解决IE6的不透明问题 */}</style><script type="text/javascript" src="jquery-1.7.2.min.js"></script><script type="text/javascript">/* 显示遮罩层 */function showOverlay() { $("#overlay").height(document.body.scrollHeight); $("#overlay").width(document.body.scrollWidth); // fadeTo第一个参数为速度，第二个为透明度 // 多重方式控制透明度，保证兼容性，但也带来修改麻烦的问题 $("#overlay").fadeTo(200, 0.5); // 解决窗口缩小时放大后不全屏遮罩的问题 // 简单来说，就是窗口重置的问题 $(window).resize(function(){ $("#overlay").height(document.body.scrollHeight); $("#overlay").width(document.body.scrollWidth); });}/* 隐藏覆盖层 */function hideOverlay() { $("#overlay").fadeOut(200);}</script></head><body><button onClick="showOverlay();" style=" width:100px; height:60px; margin:40px auto 40px auto; display:block;">打开遮罩层</button><button onClick="hideOverlay();" style=" width:100px; height:60px; z-index:101; display:block; position:absolute; left:10px; top:10px;">关闭遮罩层</button><div style="height:10000px;"></div><div id="overlay"></div></body></html>原文：http://www.cnblogs.com/sjqq/p/6361493.html