iframe的子页面怎样操作父页屏蔽页面弹出层效果

<style type="text/css">

#BgLayer {

background: #939393 none repeat scroll 0 0;

height:100%;

width:100%;

left:0;

top:0;

filter: alpha(opacity=80); /* IE */

-moz-opacity: 0.8; /* Moz + FF */

z-index: 10000;

}

#Layer {

width: 400px;

height: 400px;

margin: -180px 0 0 -170px;

left: 50%;

top: 50%;

position: absolute;

background: #FFF;

z-index: 10001;

border: 1px solid #1B5BAC;

}

</style>

<script type="text/javascript">

/*显示页面*/

function showDiv) {

var bg = document.getElementById("BgLayer");

var con = document.getElementById("Layer");

//var w = document.documentElement.clientWidth; //网页可见区域宽

//var h = document.documentElement.clientHeight;//网页可见区域高

var w = document.body.scrollWidth; //网页正文全文宽

var h = document.body.scrollHeight; //网页正文全文高

// alert(w+"-"+h);

bg.style.display = "";

bg.style.width = w + "px";

bg.style.height = h + "px";

con.style.display = "";

}

/*关闭*/

function closeDiv() {

var bg = document.getElementById("BgLayer");

var con = document.getElementById("Layer");

bg.style.display = "none";

con.style.display = "none";

}

</script>

<a href="javascript:void(0)" onclick="parent.window.showDiv()">查看</a>