Document = function()
{
    var de = document.documentElement;
    var body = document.body;
    this.width = de.clientWidth || body.clientWidth || window.innerWidth;
    this.height = de.clientHeight>body.clientHeight?de.clientHeight:0;
    this.height =  this.height || body.clientHeight || window.innerHeight;

    this.scrollTop = de.scrollTop || body.scrollTop;
    this.scrollLeft = de.scrollLeft || body.scrollLeft;
    this.scrollWidth = de.scrollWidth > body.scrollWidth ? de.scrollWidth : body.scrollWidth;
    this.scrollHeight = de.scrollHeight > body.scrollHeight ? de.scrollHeight : body.scrollHeight;
}

darkMask = function()
{
	var a = document.body;
    var doc = new Document();
    var o = 70;

	var objBrother = a.childNodes[0];
	var b = document.createElement('div');
	b.setAttribute('id','qyt_darkMask');
	b.style.textAlign = "center";
	b.style.position = "absolute";
	b.style.top = "0px";
	b.style.left = "0px";
	b.style.opacity = (o / 100);
	b.style.MozOpacity = (o / 100);
	b.style.KhtmlOpacity = (o / 100);
	b.style.filter = "alpha(opacity=" +o+ ")";
	b.style.margin = "0px";
	b.style.padding = "0px";
	b.style.backgroundColor = "#EEEEEE";
	b.style.width = doc.width +"px";
	b.style.height = doc.height +"px";
	a.appendChild(b);
}

disDarkMask = function()
{
    var obj = $("qyt_darkMask");
    document.body.removeChild(obj);
    obj = null;
}