var SelectDiv;

//显示窗口和遮罩层。
function setDiv(showdiv){
    setDiv(showdiv,'');
}

function setDiv(showdiv,parentdiv){
    //如果遮罩背景存在，先移除
    var Bigdiv = document.getElementById("BigDiv");
    if(Bigdiv!=null)
    {
	    document.body.removeChild(Bigdiv); 
    }

	//创建遮罩背景
	var maskDiv = document.createElement("div");
	maskDiv.setAttribute("id","BigDiv");
	maskDiv.style.position = "absolute";
	maskDiv.style.top = "0px";
	maskDiv.style.left = "0px";
	maskDiv.style.background = "#777";
	maskDiv.style.filter = "Alpha(opacity=70);";
	maskDiv.style.opacity = "0.3";
	maskDiv.style.zIndex = "999";
	document.body.appendChild(maskDiv);
	
	//创建遮罩iframe
	var maskIframe = document.createElement("iframe");
	maskIframe.setAttribute("id","BigIframe");
	maskIframe.style.position = "absolute";
	maskIframe.style.filter = "Alpha(opacity=0);";
	maskIframe.style.zIndex = "-1";
	maskIframe.style.width = "99%";
	maskIframe.style.height = "100%";
	maskDiv.appendChild(maskIframe);
	
	//显示弹出层
	var MyDiv =document.getElementById(showdiv);
	MyDiv.style.display = "block";
	var ParentDiv = document.getElementById(parentdiv);
	if(ParentDiv) ParentDiv.appendChild(MyDiv);
	else document.body.appendChild(MyDiv);
	
	//当前选中的弹出层
	SelectDiv = showdiv;
	
	//设置层的宽高
	setPos();
	
	if(document.all){
	    //弹出层跟随窗口的变化
		window.attachEvent("onresize", setPos);
		//弹出层跟随滚动条滚动
		window.attachEvent("onscroll", setPos);
	}else{
	    //弹出层跟随窗口的变化
		window.addEventListener("resize", setPos, false);
		//弹出层跟随滚动条滚动
		window.addEventListener("scroll", setPos, false);
	}
}

//关闭窗口和遮罩层。
function closeDiv(showdiv){
	var Bigdiv = document.getElementById("BigDiv");
	var Mydiv = document.getElementById(showdiv);
	document.body.removeChild(Bigdiv); 
	Mydiv.style.display="none";
}
	
//设置层的宽高
function setPos(){
    var MyDiv = document.getElementById(SelectDiv);
    var Bigdiv = document.getElementById("BigDiv");
    
    if(MyDiv != null)
    {
        var MyDiv_w = getStyle(MyDiv,"width");
	    var MyDiv_h = getStyle(MyDiv,"height");
	    
	    MyDiv_w = parseInt(MyDiv_w); //去掉 单位 "px"
	
	    if(isNaN(MyDiv_w))
	    {
	        MyDiv_w = 0;
	    }
		
	    MyDiv_h = parseInt(MyDiv_h);
		
	    if(isNaN(MyDiv_h))
	    {
	        MyDiv_h = 0;
	    }
    
	    MyDiv.style.left = (document.documentElement.clientWidth/2 + document.documentElement.scrollLeft - MyDiv_w/2) + "px";
	    MyDiv.style.top = (document.documentElement.clientHeight/3 + document.documentElement.scrollTop - MyDiv_h/3) + "px";  
	}
	
	if(Bigdiv != null)
	{
	    Bigdiv.style.width = Math.max(document.documentElement.scrollWidth, document.documentElement.clientWidth) + "px";
	    Bigdiv.style.height = Math.max(document.documentElement.scrollHeight, document.documentElement.clientHeight) + "px";
	}
}
			
//解决外嵌样式style , 用js获取不到的问题。
function getStyle(elem, name){
    try
    {
		if(elem.style[name])
			return elem.style[name];
		else if(elem.currentStyle)	//ie
			return elem.currentStyle[name];
		else if(document.defaultView && document.defaultView.getComputedStyle){	//w3c
			name = name.replace(/([A-Z])/g,"-$1");
			name = name.toLowerCase();
			
			var s = document.defaultView.getComputedStyle(elem,"");
			return s && s.getPropertyValue(name);
		} else
			return null
	}
	catch(e) { }
}

//显示当前DIV
function setDiv2(showdiv2){
	//显示弹出层
	var MyDiv =document.getElementById(showdiv2);
	MyDiv.style.display = "block";
}

//关闭当前DIV
function closeDiv2(showdiv2){
	var Mydiv = document.getElementById(showdiv2);
	Mydiv.style.display="none";
}