JS取屏幕坐标相关
1,设置Div居中
<div id="Layer1" style="position:absolute; left:expression((document.body.offsetWidth-200)/2); top:expression((document.body.offsetHeight-100)/2); width:200; height:100; background:red; z-index:1"></div>
<div id="Layer1" style="position:absolute; left:expression((document.body.offsetWidth-200)/2); top:expression((document.body.offsetHeight-100)/2); width:200; height:100; background:red; z-index:1"></div>
