iframe子页面操作父页面并实现屏蔽页面弹出层效

<!-- 右侧iframe开始 -->
<div id="resDiv" class="resDiv">
<iframe name="res" class="iframestyle" allowtransparency="true" src="son.html" frameborder="0" scrolling="no"></iframe>
</div>
<!-- 右侧iframe结束 -->

<!--弹出的登录页面层-->
<div id="mapLayer" style="display: none; " >
<input type="button" value="关闭" onclick="closeMap()" />
</div>
<!--屏蔽层，用来透明的屏蔽整个页面-->
<div id="mapBgLayer" style="position:absolute; display: none;"></div>

<style type="text/css">
#BgLayer {
background: #939393 none repeat scroll 0 0;
height:100%;
width:100%;
left:0;
: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%;
: 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>