HTML页面弹出自定义对话框带遮蔽罩（使用JavaScript）

转载：http://blog.sina.com.cn/s/blog_610f47c50100ohe4.html

原理其实很简单：首先绘制弹出的自定义对话框，将其使用display:none隐藏，因为设置为none，其在页面中并不占用空间；

遮蔽罩使用一个div，然后将其宽高设置为整个显示窗口大小，配置其透明度，在将其z-index属性大于主页面的z-index的值，也就是遮蔽层在主页面上方，如此即可

事先隐藏一个div，在需要的时候调出显示既可。

<!--以下代码从网上多处学习整合而成，由于来源不一，并经过自行修改，请原谅未作注明-->

<script type="text/javascript">
var docEle = function()
{
   return document.getElementByIdx_x(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_x("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_x("div");
     newDiv.id = _id;
     newDiv.style.position = "absolute";
     newDiv.style.zIndex = "9999";
     newDivWidth = 250;
     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 = document.getElementByIdx_x("HideDlg").innerHTML;
     newDiv.innerHTML+= "&nbsp"
     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_x("a");
    newA.href = "#";
    newA.innerHTML = "Cancel";
    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);
}

function closeDiv()
{
    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;
}
</script>
<!--img控件，点击触发-->
<div id="1" align="center" style="cursor:pointer">
<br>
<img src="1.png" alt="" style="width:123px;height:43px;" onclick="openNewDiv('newDiv');return false;"/>
</div>
<!--隐藏的div，随意修改-->
<div id="HideDlg" style="display:none;">
<input name="Btn" type="button" value="1" onclick="window.location.href='http://1.aspx'
</div>

　　

优点：显示效果好，无边框，弹出后始终保持在屏幕中部，主页面变灰。
缺点：代码复杂。
注意：如果是在motherpage中添加，触发控件如果为<input img>的时候，可能会触发页面自刷屏导致页面跳转被自己覆盖