html 锁定页面(js遮罩层弹出div效果)

<htmlxmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312"/>
<title>UntitledDocument</title>
<script>
function createIframe(){
//mask遮罩层
var newMask=document.createElement("div");
newMask.id="mDiv";
newMask.style.position="absolute";
newMask.style.zIndex="1";
_scrollWidth=Math.max(document.body.scrollWidth,document.documentElement.scrollWidth);
_scrollHeight=Math.max(document.body.scrollHeight,document.documentElement.scrollHeight);
// _scrollHeight = Math.max(document.body.offsetHeight,document.documentElement.scrollHeight);
newMask.style.width=_scrollWidth+"px";
newMask.style.height=_scrollHeight+"px";
newMask.style.top="0px";
newMask.style.left="0px";
newMask.style.background="#33393C";
//newMask.style.background = "#FFFFFF";
newMask.style.filter="alpha(opacity=40)";
newMask.style.opacity="0.40";
newMask.style.display='none';
var objDiv=document.createElement("DIV");
objDiv.id="div1";
objDiv.name="div1";
objDiv.style.width="480px";
objDiv.style.height="200px";
objDiv.style.left=(_scrollWidth-480)/2+"px";
objDiv.style.top=(_scrollHeight-200)/2+"px";
objDiv.style.position="absolute";
objDiv.style.zIndex="2"; //加了这个语句让objDiv浮在newMask之上
objDiv.style.display="none"; //让objDiv预先隐藏
objDiv.innerHTML=' <div id="drag" style="position:absolute;height:20px;width:100%;z-index:10001;top:0; background-color:#0033FF;cursor:move ;" align="right"> <input type=button value="X" onclick="HideIframe(document.getElementById(\'mDiv\'),document.getElementById(\'div1\'));"/> </div>';
//更改了X按钮为触发关闭事件。
objDiv.style.border="solid #0033FF 3px;";
var frm=document.createElement("iframe");
frm.id="ifrm";
frm.name="ifrm";
frm.style.position="absolute";
frm.style.width="100%";
frm.style.height=180;
frm.style.top=20;
frm.style.display='';
frm.frameborder=0;
objDiv.appendChild(frm);
// newMask.appendChild(objDiv); //问题出在这里：你把frame所在的div变成了 newMask的子元素，当newMask透明度更改时，当然会影响到frame
document.body.appendChild(newMask);
document.body.appendChild(objDiv);
var objDrag=document.getElementById("drag");
var drag=false;
var dragX=0;
var dragY=0;
objDrag.attachEvent("onmousedown",startDrag);
function startDrag(){
if(event.button==1&&event.srcElement.tagName.toUpperCase()=="DIV"){
objDrag.setCapture();
objDrag.style.background="#0000CC";
drag=true;
dragX=event.clientX;
dragY=event.clientY;
}
};
objDrag.attachEvent("onmousemove",Drag);
function Drag(){
if(drag){
var oldwin=objDrag.parentNode;
oldwin.style.left=oldwin.offsetLeft+event.clientX-dragX;
oldwin.style.top=oldwin.offsetTop+event.clientY-dragY;
oldwin.style.left=event.clientX-100;
oldwin.style.top=event.clientY-10;
dragX=event.clientX;
dragY=event.clientY;
}
};
objDrag.attachEvent("onmouseup",stopDrag);
function stopDrag(){
objDrag.style.background="#0033FF";
objDrag.releaseCapture();
drag=false;
};
}
function htmlEditor(){
var frm=document.getElementById("ifrm");
var objDiv=document.getElementById("div1");
var mDiv=document.getElementById("mDiv");
mDiv.style.display='';
var iframeTextContent='';
iframeTextContent+=' <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">';
iframeTextContent+=' <html xmlns="http://www.w3.org/1999/xhtml">';
iframeTextContent+=' <head>';
iframeTextContent+=' <meta http-equiv="Content-Type" content="text/html; charset=gb2312" />';
iframeTextContent+=' </head>';
iframeTextContent+=' <body>';
iframeTextContent+=' <table>';
iframeTextContent+=' <tr>';
iframeTextContent+=' <td>Name </td>';
iframeTextContent+=' <td> <input type="text" value="" /> </td>';
iframeTextContent+=' </tr>';
iframeTextContent+=' <tr>';
iframeTextContent+=' <td>Email </td>';
iframeTextContent+=' <td> <input type="text" value="" /> </td>';
iframeTextContent+=' </tr>';
iframeTextContent+=' <tr>';
iframeTextContent+=' <td> <input type="button" id="btGo" value="Go" /> </td>';
iframeTextContent+=' </tr>';
iframeTextContent+=' </table>';
iframeTextContent+=' </body>';
iframeTextContent+=' </html>';
frm.contentWindow.document.designMode='off';
frm.contentWindow.document.open();
frm.contentWindow.document.write(iframeTextContent);
frm.contentWindow.document.close();
objDiv.style.display = ""; //显示浮动的div
var objGo=frm.contentWindow.document.getElementById("btGo");
objGo.attachEvent("onclick",function (){
HideIframe(mDiv,objDiv);
});
}
function HideIframe(mDiv,objDiv){
mDiv.style.display='none';
objDiv.style.display = "none"; //隐藏浮动的div
}
</script>
</head>
<body onLoad="createIframe()">
<table>
<tr>
<td>aa</td>
<td><input type="text"/></td>
</tr>
<tr>
<td>bb</td>
<td><input type="text"/></td>
</tr>
</table>
[br]
<input type="button"id="tt"name="tt"value="Click"onClick="htmlEditor()"/>
</body>
</html>