HTML代码：
js代码：
测试源码如下：
<!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" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no">
<title>无标题文档</title>
<style>
.layer_a{position:fixed;top:0px;left:0px;z-index:10;height:100%;width:100%;}
.bg_layer{position:absolute;z-index:10;top:0px;left:0px;width:100%;height:100%;background-color:#000000;opacity:0.3;}
.layer_a .layer_connect{position:absolute;bottom:85px;left:10%;z-index:11;width:80%;max-height:70%;overflow:hidden;overflow-y:auto;line-height:30px;padding:10px;border-radius:4px;background-color:#fff;}
.layer_a label{padding-left:10px;}
</style>
</head>