function OpenAlter(AlterParameter){
	if(!document.getElementById("my_bg")){
		mybg = document.createElement("div");
		mybg.setAttribute("id","my_bg");
		mybg.style.background = "#000";
		if(navigator.userAgent.indexOf("MSIE")>0) { 
			if(document.body.scrollHeight < window.screen.availHeight){
				mybg.style.width = document.body.scrollWidth+"px";//现在宽度是定死的，所以此处写法无所谓
				mybg.style.height = window.screen.availHeight+"px";
			}else{
				mybg.style.width = document.body.scrollWidth+"px";
				mybg.style.height = document.body.scrollHeight+"px";
			}
		} 
		if(isFirefox=navigator.userAgent.indexOf("Firefox")>0){ 
			mybg.style.width =document.documentElement.scrollWidth+"px";
			mybg.style.height = document.documentElement.scrollHeight+"px";
		} 
		mybg.style.position = "absolute";
		mybg.style.top = "0";
		mybg.style.left = "0";
		mybg.style.opacity = "0.3";
		mybg.style.filter = "Alpha(opacity=10)";
		mybg.style.zIndex = "500";
		document.body.appendChild(mybg);
	}
	else{
		document.getElementById("my_bg").style.display = "block";
	}
	var broY = GetScrollY(); //取得已滚动过去的高度
	var CreatePF = document.getElementById(AlterParameter);
	CreatePF.style.display = "block";
	CreatePF.style.position = "absolute";
	CreatePF.style.top = "300px";
	CreatePF.style.left = "500px";
	CreatePF.style.marginTop = (broY) + "px"; 
	CreatePF.style.marginLeft = "0px";
	CreatePF.style.zIndex = "1000";
}
/*弹出框 关闭*/
function CloseAlter(AlterParameter){
	document.getElementById(AlterParameter).style.display = "none";
	if(AlterParameter != "alert_venue_friends")
	{
		document.getElementById("my_bg").style.display = "none";
	}
}
/* 获取网页被卷去的高，制作浮动窗体可用 */
function GetScrollY(){        
    if (typeof window.pageYOffset == 'number'){
        return window.pageYOffset;
    }

    var CompatMode = window.document.compatMode;
    var DocumentElement = window.document.documentElement;

    if ((typeof CompatMode == 'string') && (CompatMode.indexOf('CSS') >= 0) && (DocumentElement) && (typeof DocumentElement.getAttribute("scrollTop") == 'number')){
        return DocumentElement.getAttribute("scrollTop");
     } 

    var Body = window.document.body ;

    if ((Body) && (typeof Body.getAttribute("scrollTop") == 'number')){
        return Body.getAttribute("scrollTop");
    }

    return 0;
}
function Browser(){
	var ua, s, i;
	this.isIE = false;
	this.isNS = false;
	this.isOP = false;
	this.isSF = false;
	ua = navigator.userAgent.toLowerCase();
	s = "opera";
	if ((i = ua.indexOf(s)) >= 0){
		this.isOP = true;return;
	}
	s = "msie";
	if ((i = ua.indexOf(s)) >= 0) {
		this.isIE = true;return;
	}
	s = "netscape6/";
	if ((i = ua.indexOf(s)) >= 0) {
		this.isNS = true;return;
		}
	s = "gecko";
	if ((i = ua.indexOf(s)) >= 0) {
		this.isNS = true;
		return;
	}
	s = "safari";
	if ((i = ua.indexOf(s)) >= 0) {
		this.isSF = true;
		return;
	}
}
 function mcl(show, div, btn, over, padd){
	var objdiv = document.getElementById(div);
	var objbtn = document.getElementById(btn);
	if (objdiv && objbtn){
		var browser = new Browser();
		if (show){
			objdiv.style.display = "block";
			if (browser.isIE && over){
				var allselect = document.getElementsByTagName("select");
				for (var i=0; i<allselect.length; i++){
					allselect[i].style.visibility = "hidden";
				}
			}
			objdiv.style.top = (objbtn.offsetTop + objbtn.offsetHeight - 2) + "px";
			objdiv.style.left = (objbtn.offsetLeft - (padd?0:50)) + "px";
		}else{
			objdiv.style.display = "none";
			if (browser.isIE && over){
				var allselect = document.getElementsByName("select");
				for (var i=0; i<allselect.length; i++){
					allselect[i].style.visibility = "visible";
				}
			}
		}
	}
}