ajax类

function chaf(){
	var ajax=Ajax();
	var username='';
	//return;
	ajax.get("getpw.php?do=chaf&username="+ encodeURI(username),function(data){
	$$$('con3').innerHTML=data;
	});
	}

function Ajax(recvType){

    var aj=new Object();
    aj.recvType=recvType ? recvType.toUpperCase() : 'HTML';  //向形参中传递的文件类型
     aj.targetUrl='';
    aj.sendString='';
    aj.resultHandle=null;

    /*创建XMLHttpRequest对象*/
    aj.createXMLHttpRequest=function(){
        var xmlHttp = false;
        if(window.XMLHttpRequest){ //在非IE中创建XMLHttpRequest对象
            xmlHttp = new XMLHttpRequest();
        }else if(window.ActiveXObject){
            try{
                xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); //按新版IE创建
            }catch(error1){ //创建失败
                try{
                    xmlHttp = new ActiveXobject("Microsoft.XMLHttp"); //按老版IE创建
                }catch(error2){ //创建失败
                    xmlHttp = false;
                }
            }
        }
        return xmlHttp;
    }

    aj.XMLHttpRequest=aj.createXMLHttpRequest();

    /*处理服务器的响应*/
    aj.processHandle=function(){
        if(aj.XMLHttpRequest.readyState == 4){
            if(aj.XMLHttpRequest.status == 200){
                if(aj.recvType=="HTML")
                    aj.resultHandle(aj.XMLHttpRequest.responseText);
                else if(aj.recvType=="XML")
                    aj.resultHandle(aj.XMLHttpRequest.responseXML);
            }
        }
    }

    /*定义使用get方法传递的方法*/
    aj.get=function(targetUrl, resultHandle){
        aj.targetUrl=targetUrl;    
        
        if(resultHandle!=null){
            aj.XMLHttpRequest.onreadystatechange=aj.processHandle;    
            aj.resultHandle=resultHandle;    
        }
        if(window.XMLHttpRequest){
            aj.XMLHttpRequest.open("get", aj.targetUrl);
            aj.XMLHttpRequest.send(null);
        }else{
            aj.XMLHttpRequest.open("get", aj.targetUrl, true);
            aj.XMLHttpRequest.send();
        }
        
    }

    /*定义使用post方法传递的方法*/
    aj.post=function(targetUrl, sendString, resultHandle){
        aj.targetUrl=targetUrl;

        if(typeof(sendString)=="object"){
            var str="";
            for(var pro in sendString){
                str+=pro+"="+sendString[pro]+"&";    
            }
            aj.sendString=str.substr(0, str.length-1);
        }else{
            aj.sendString=sendString;
        }

        if(resultHandle!=null){
            aj.XMLHttpRequest.onreadystatechange=aj.processHandle;    
            aj.resultHandle=resultHandle;    
        }

        aj.XMLHttpRequest.open("post", targetUrl);
        aj.XMLHttpRequest.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        aj.XMLHttpRequest.send(aj.sendString);
        
    }

    return aj;
}




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