var userAgent = navigator.userAgent.toLowerCase();
var is_opera = userAgent.indexOf('opera') != -1 && opera.version();
var is_moz = (navigator.product == 'Gecko') && userAgent.substr(userAgent.indexOf('firefox') + 8, 3);
var is_ie = (userAgent.indexOf('msie') != -1 && !is_opera) && userAgent.substr(userAgent.indexOf('msie') + 5, 3);
var is_mac = userAgent.indexOf('mac') != -1;
var ajaxdebug = 1;

var IMGDIR='dd';

function $(id) {
    return document.getElementById(id);
}

function isUndefined(variable) {
    return typeof variable == 'undefined' ? true : false;
}


/**
* 弹出锁定层
*@param txt 弹出的文字 也支持html代码
*@param url 跳转地址 默认不跳转
*@param timeout 自动关闭时间 以毫秒为单位 默认2000
*@target 跳转目标 _self/_parent/_top 默认_self
*@lockcolor 锁屏颜色 默认#ccc
*@lockopacity 锁屏不透明度 默认30
*/
var alertdivInstance=null;
alertdiv = function(txt,url,timeout,target,islock,lockcolor,lockopacity) 
{ 
    if(isUndefined(txt) || txt==""){return false;}
    if(isUndefined(url)){url="";}
    if(isUndefined(timeout) || timeout==""){timeout=2000;}
    if(isUndefined(target) || timeout==""){target="current";}
    if(isUndefined(islock) || islock==""){islock=1;} 
    if(isUndefined(islock) || islock==""){islock=1;}
    if(isUndefined(lockcolor) || lockcolor==""){lockcolor="#ccc";}
    if(isUndefined(lockopacity) || lockopacity==""){lockopacity="50";}
    var body=document.body;
    alertdivInstance=this;
    
    if(lockopacity==100) {body.firstChild.innerHTML="";}
    
    var shield = document.createElement("DIV");  
    var alertFram=document.createElement("DIV");
    
    alertFram.id="alertFram";
    var scrollTop=document.documentElement.scrollTop;
       if(!window.ActiveXObject)	//火狐
    {
    	divTop=document.documentElement.scrollHeight;    	    	
	}
    else						//IE7
    {
	    divTop=document.body.clientHeight;    
	    if(document.body.clientHeight<document.documentElement.clientHeight){
	    	divTop=document.documentElement.clientHeight;
	    }
    }
    if(islock){with(shield.style){id="lockdivid";position="absolute";left="0px";top="0px";filter="alpha(opacity="+lockopacity+")";opacity = parseFloat(lockopacity/100);width="100%";height=divTop+"px";background="#ccc";textAlign="center";zIndex="9999";}}
    with(alertFram.style){position="absolute";textAlign="center";}
    
    if(is_ie){with(body.firstChild){appendChild(shield);appendChild(alertFram);}}
    else{with(body){appendChild(shield);appendChild(alertFram);}}
            
    
    alertFram.innerHTML=txt;
    with(alertFram.style)
    {
        left=parseInt((body.clientWidth/2)-(alertFram.offsetWidth/2))+"px";
        if(!window.ActiveXObject)	//火狐
    	{    		    		        		
        	top=scrollTop?(scrollTop+((document.documentElement.clientHeight-alertFram.offsetHeight)/2)) +"px":((document.documentElement.clientHeight-alertFram.offsetHeight)/2)+'px';  
    	}
    	else
    	{    		    		
    		top=scrollTop?(scrollTop + ((document.documentElement.offsetHeight-alertFram.offsetHeight)/2)) +"px":((document.documentElement.offsetHeight-alertFram.offsetHeight)/2)+'px';  
    	}
        zIndex="10000";   
    }
    if(url!="") {var astr="<a href='"+url+"' target='"+target+"'>页面即将跳转</a>";var msgTextObj=alertFram.firstChild;msgTextObj.innerHTML+=astr;}
    this.doOk=function(){ if(url != "") {switch(target){case '_self':{window.location=url;break;}case '_parent':{window.parent.location=url;break;}case '_top':{window.top.location=url;break;}default:break;}}else{alertFram.style.display="none";shield.style.display="none";}alertFram.innerHTML="";alertdivInstance=null;}
    if(timeout > 0)
    {
        _this=this; var doOkName=function() {_this.doOk();} 
        setTimeout(doOkName,timeout);
    }
}

var xmlHttp; 
function createXmlHttpRequest()
{
    if(window.XMLHttpRequest)
    {       
        xmlHttp=new XMLHttpRequest();
        if(xmlHttp.overrideMimeType) {xmlHttp.overrideMimeType("text/xml");}
    }
    else if(window.ActiveXObject)
    {
        try {xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");}
        catch(e) {xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");}
    }
    if(!xmlHttp) {window.alert("your browser cant create XML httpRequest object!");}
    
    return xmlHttp;
}