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<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
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<body>
<script type="text/javascript">
var docEle = function()
{
    return document.getElementById(arguments[0]) || false;
}

function openNewDiv(_id)
{
    var m = "mask";
    if (docEle(_id)) document.body.removeChild(docEle(_id));
    if (docEle(m)) document.body.removeChild(docEle(m));
   
    //mask遮罩层

    var newMask = document.createElement("div");
    newMask.id = m;
    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);
    newMask.style.width = _scrollWidth + "px";
    newMask.style.height = _scrollHeight + "px";
    newMask.style.top = "0px";
    newMask.style.left = "0px";
    newMask.style.background = "#33393C";
    newMask.style.filter = "alpha(opacity=40)";
    newMask.style.opacity = "0.40";
    document.body.appendChild(newMask);
   
    //新弹出层

    var newDiv = document.createElement("div");
    newDiv.id = _id;
    newDiv.style.position = "absolute";
    newDiv.style.zIndex = "9999";
    newDivWidth = 400;
    newDivHeight = 200;
    newDiv.style.width = newDivWidth + "px";
    newDiv.style.height = newDivHeight + "px";
    newDiv.style.top = (document.body.scrollTop + document.body.clientHeight/2 - newDivHeight/2) + "px";
    newDiv.style.left = (document.body.scrollLeft + document.body.clientWidth/2 - newDivWidth/2) + "px";
    newDiv.style.background = "#EFEFEF";
    newDiv.style.border = "1px solid #860001";
    newDiv.style.padding = "5px";
    newDiv.innerHTML = "弹出层内容 ";
    document.body.appendChild(newDiv);
   
    //弹出层滚动居中

    function newDivCenter()
    {
        newDiv.style.top = (document.body.scrollTop + document.body.clientHeight/2 - newDivHeight/2) + "px";
        newDiv.style.left = (document.body.scrollLeft + document.body.clientWidth/2 - newDivWidth/2) + "px";
    }
    if(document.all)
    {
        window.attachEvent("onscroll",newDivCenter);
    }
    else
    {
        window.addEventListener('scroll',newDivCenter,false);
    }
   
    //关闭新图层和mask遮罩层

    var newA = document.createElement("a");
    newA.href = "#";
    newA.innerHTML = "关闭";
    newA.onclick = function()
    {
        if(document.all)
        {
            window.detachEvent("onscroll",newDivCenter);
        }
        else
        {
            window.removeEventListener('scroll',newDivCenter,false);
        }
        document.body.removeChild(docEle(_id));
        document.body.removeChild(docEle(m));
        return false;
    }
    newDiv.appendChild(newA);
}
</script>
<body>
<a onclick="openNewDiv('newDiv');return false;" style="cursor:pointer">qifei弹层</a>
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