<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>全屏div</title>
<style>
html,body {
margin:0;
height:100%;
}
#log_window {
width:200px;
height:200px;
background-color:#FF0;
margin: auto;
position: absolute;
z-index:3;
top: 0;
bottom: 0;
left: 0;
right: 0;
}
</style>
<script>
</script>
</head>
<body>
<div id="log_window">
</div>
</body>
</html>
