网站div浮动层同时网站背景变灰代码兼容firefox,谷歌浏览器(Chrome)

网站div浮动层同时网站背景变灰代码兼容firefox,谷歌浏览器(Chrome)效果图：

Sign in处代码：Sign in

function ShowLoginWindow()
{
   if(document.getElementById("fullbg"))
{
   document.body.removeChild(document.getElementById("fullbg"));
}
if(document.getElementById("deliverywin"))
{
   document.body.removeChild(document.getElementById("deliverywin"));
}  
    deliverywinopen();
}

function deliverywinopen()
{
var bgDiv=document.createElement("div");
bgDiv.id="fullbg";
bgDiv.className="fullwinbg";
bgDiv.style.px";
var scrollHeight=document.body.scrollHeight+20;
bgDiv.style.px";
bgDiv.innerHTML="";
document.body.appendChild(bgDiv);
var deliverywin=document.createElement("div");
deliverywin.id="deliverywin";
deliverywin.className="deliverywindow";
deliverywin.innerHTML="";
/* var mouse=mouseCoords(document.getElementById("Table13"));
var x=mouse.x+217;
var y=mouse.y+130;
deliverywin.style.left=x+"px";
deliverywin.style.top=y+"px";*/
document.body.appendChild(deliverywin);
centerwh(deliverywin);
}

function centerwh(obj)
{
    var h1 = document.body.clientHeight;
    var h2 = document.documentElement.clientHeight;
    var isXhtml = (h2<=h1&&h2!=0)?true:false;
    var body = isXhtml?document.documentElement:document.body;
  
    var wh={left:0,top:0};
    var vwh={w:0,h:0};
    vwh.w=navigator.userAgent.indexOf('MSIE') >= 0?parseInt(body.clientWidth):parseInt(window.innerWidth);
    vwh.h=navigator.userAgent.indexOf('MSIE') >= 0?parseInt(body.clientHeight):parseInt(window.innerHeight);
    wh.left=(vwh.w/2)-108;
    wh.top=document.documentElement.scrollTop+document.body.scrollTop+(vwh.h/2)-150;这个地方要注意：即获取高度时使用document.documentElement.scrollTop+document.body.scrollTop，经测试，代码在IE、Firefox、Chrome下都能显示正常了。

document.getElementById("deliverywin").style.top = wh.top + "px";
document.getElementById("deliverywin").style.left = wh.left + "px";

}

function windowclose()
{
if(document.getElementById("fullbg"))
{
   document.body.removeChild(document.getElementById("fullbg"));
}
if(document.getElementById("deliverywin"))
{
   document.body.removeChild(document.getElementById("deliverywin"));
}
}

在loginifram.aspx页面处的关闭代码：close