Check it:
<html>
<head>
<title>EXAMPLE</title>
<style>
.overlay{
display: none;
position: absolute;
top: 0%;
left: 0%;
width: 100%;
height: 100%;
background-color: gray;
z-index:1001;
-moz-opacity: 0.8;
opacity:.80;
filter: alpha(opacity=50);
}
.content {
display: none;
position: absolute;
top: 25%;
left: 25%;
width: 50%;
height: 50%;
padding: 16px;
border: 16px solid blue;
background-color: white;
z-index:1002;
overflow: auto;
}
</style>
</head>
<body>
<p>灰化背景
<a href="javascript:void(0)" onclick="document.getElementById('light').style.display='block'; document.getElementById('fade').style.display='block'">点击</a>打开窗口
</p>
<div id="light" class="content">
弹出窗口的内容写在这里。点击<a href="javascript:void(0)" onclick="document.getElementById('light').style.display='none';document.getElementById('fade').style.display='none'">X</a>这里关闭窗口
</div>
<div id="fade" class="overlay"></div>
</body>
</html>
<head>
<title>EXAMPLE</title>
<style>
.overlay{
display: none;
position: absolute;
top: 0%;
left: 0%;
width: 100%;
height: 100%;
background-color: gray;
z-index:1001;
-moz-opacity: 0.8;
opacity:.80;
filter: alpha(opacity=50);
}
.content {
display: none;
position: absolute;
top: 25%;
left: 25%;
width: 50%;
height: 50%;
padding: 16px;
border: 16px solid blue;
background-color: white;
z-index:1002;
overflow: auto;
}
</style>
</head>
<body>
<p>灰化背景
<a href="javascript:void(0)" onclick="document.getElementById('light').style.display='block'; document.getElementById('fade').style.display='block'">点击</a>打开窗口
</p>
<div id="light" class="content">
弹出窗口的内容写在这里。点击<a href="javascript:void(0)" onclick="document.getElementById('light').style.display='none';document.getElementById('fade').style.display='none'">X</a>这里关闭窗口
</div>
<div id="fade" class="overlay"></div>
</body>
</html>