全屏DIV透明遮罩层

<!-- 这个是修改密码的弹出遮罩层 -->

<div id="coverDivId" style="position: absolute;width: 100%;height: 100%;background-color:rgb(140,146,150);display:block;
	filter:alpha(opacity=50);-moz-opacity:0.5;-khtml-opacity:0.5;opacity: 0.5;
	top: 0px;left: 0px;">
</div>