IE7 下的Ajax小问题

Question

不知道我的IE有问题还是怎么了,这个方法就是不行..
function GetXmlHttpObj()
{
var XmlHttpObj = null;
try
{ 
/**  这个也不行
if(window.ActiveXObject)
{ 
for(var i = 6;i;i--)
{ 
try
{
if( i == 2 )
{ 
XmlHttpObj = new ActiveXObject( "Microsoft.XMLHTTP" ); 
}
else
{ 
XmlHttpObj = new ActiveXObject( "Msxml2.XMLHTTP." + i + ".0" ); 
} 
XmlHttpObj.setRequestHeader("Content-Type","text/xml"); 
XmlHttpObj.setRequestHeader("Content-Type","utf-8"); 
break;
}
catch(e)
{}
}
}
else if( window.XMLHttpRequest )
{ 
XmlHttpObj = new XMLHttpRequest(); 
if (XmlHttpObj.overrideMimeType) 
{
XmlHttpObj.overrideMimeType('text/xml');
}
}
**/
       if(window.ActiveXObject){
            var ieArr=["Msxml2.XMLHTTP.6.0","Msxml2.XMLHTTP.3.0", "Msxml2.XMLHTTP","Microsoft.XMLHTTP"];               
            for(var i=0;i<ieArr.length;i++)
                {
                var xmlhttp= new ActiveXObject(ieArr[i]);
                }
                return xmlhttp;
       } else if(window.XMLHttpRequest){
               return new XMLHttpRequest();
            }       
}
catch(e)
{}
return XmlHttpObj
}

Answer 1

function GetXmlHttpObject()
{
  var xmlHttp=null;
  try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
    }
  catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    }
  return xmlHttp;
}

Answer 2

to gkw521 :IE 下"Msxml2.XMLHTTP","Microsoft.XMLHTTP"  这两个能兼容所有版本了吗.

Answer 3

不冷清啊,很热闹的
来我给你解决掉Msxml2.XMLHTTP","Microsoft.XMLHTTP不一定能兼容所有版本的.另外你不用重复这么多判断..
IE下这样就好了
  function createXMLHTTP() {
                
                    var arrSignatures = ["MSXML2.XMLHTTP.5.0", "MSXML2.XMLHTTP.4.0",
                                         "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP",
                                         "Microsoft.XMLHTTP"];
                                         
                    for (var i=0; i < arrSignatures.length; i++) {
                        try {
                        
                            var oRequest = new ActiveXObject(arrSignatures[i]);
                            
                            return oRequest;
                        
                        } catch (oError) {
                            //ignore
                        }
                    }          
                
                    throw new Error("MSXML is not installed on your system.");               
                }
                
                function getServerInfo() {
                        var oRequest = createXMLHTTP();
                        oRequest.open("get", "url", true);/*你自己的url*/
                        oRequest.onreadystatechange = function () {
                                if (oRequest.readyState == 4) {
                                alert("Status is " + oRequest.status + " (" + oRequest.statusText + ")");
                                alert("Response text is: " + oRequest.responseText);
                            }
                        }
                        oRequest.send(null);                }

Answer 4

给你一个我自己用的ajax请求结构,基本支持所有浏览器,有不明白的地方就问我吧
var net=new Object();net.READY_STATE_UNINITIALIZED=0;
net.READY_STATE_LOADING=1;
net.READY_STATE_LOADED=2;
net.READY_STATE_INTERACTIVE=3;
net.READY_STATE_COMPLETE=4;
/*--- content loader object for cross-browser requests ---*/
net.ContentLoader=function(url,onload,onerror,method,params,contentType){
    this.req=null;
    this.onload=onload;
    this.onerror=(onerror) ? onerror : this.defaultError;
    this.loadXMLDoc(url,method,params,contentType);
}net.ContentLoader.prototype={
    loadXMLDoc:function(url,method,params,contentType){
        if (!method){
            method="GET";
        }
        if (!contentType && method=="POST"){
            contentType='application/x-www-form-urlencoded';
        }
        if (window.XMLHttpRequest){
            this.req=new XMLHttpRequest();
        } else if (window.ActiveXObject){
            this.req=new ActiveXObject("Microsoft.XMLHTTP");
        }
        if (this.req){
            try{
                var loader=this;
                this.req.onreadystatechange=function(){
                    loader.onReadyState.call(loader);
                }
                this.req.open(method,url,true);
                if (contentType){
                    this.req.setRequestHeader('Content-Type', contentType);
                }
                this.req.send(params);
            }catch (err){
                this.onerror.call(this);
            }
        }
    },    onReadyState:function(){
        var req=this.req;
        var ready=req.readyState;
        var httpStatus=req.status;
        if (ready==net.READY_STATE_COMPLETE){
            if (httpStatus==200 || httpStatus==0){
                this.onload.call(this);
            }else{
                this.onerror.call(this);
            }
        }
    },    defaultError:function(){
        alert("error fetching data!"
            +"\n\nreadyState:"+this.req.readyState
            +"\nstatus: "+this.req.status
            +"\nheaders: "+this.req.getAllResponseHeaders());
    }
}

Answer 5

你写的请求中盲目的判断太多
只需要判断 if (window.XMLHttpRequest){  //支持FireFox
            this.req=new XMLHttpRequest();
        } else if (window.ActiveXObject){ //支持IE
            this.req=new ActiveXObject("Microsoft.XMLHTTP");
        }

Answer 6

怎么用这么多判断啊  一般的就这样写就可以了
var xmlHttp;function validateEmail() {   var email = document.getElementById("email");   var url = "validate?email=" + escape(email.value);   if (window.ActiveXObject) {     xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");   }   else if (window.XMLHttpRequest) {     xmlHttp = new XMLHttpRequest();   }

Answer 7

to BeenZ:
谢谢,我好好研究下..
to xiaofan_sap:我一般情况下也是你这么写,但是这个IE7不行..多判断几个也是为了多兼容几个浏览器.不兼容的话,主要功能就显示不出来了..

Answer 8

不是这样的,LZ,一般现在主要兼容问题就在IE,FF,你只需要根据这2个浏览器的支持来判断就行了的,当然也有特殊情况

Answer 9

2个问题
1. try...catch应写在for循环内
2. return也最好写在for循环内,否则相当于每次返回的都是new ActiveXObject("Microsoft.XMLHTTP"),又因为没有try...catch,从高版本的Msxml2.XMLHTTP.6.0开始创建时可能导致创建失败if(window.ActiveXObject){
            var ies=["Msxml2.XMLHTTP.6.0","Msxml2.XMLHTTP.5.0","Msxml2.XMLHTTP.4.0","Msxml2.XMLHTTP.3.0","Msxml2.XMLHTTP","Microsoft.XMLHTTP"];
            for(var i=0;i<ies.length;i++){
                try{
                    return new ActiveXObject(ies[i]);//从较高版本创建以取得较好的性能
                }catch(e){}
            }
        }
        else if(window.XMLHttpRequest){
            return new XMLHttpRequest();
        }

Answer 10

下班后没电脑,晚上就没测试了.
上午测了下 奇怪的发现:  var xmlHttp=null;
               alert("1");   
  
  
    if(window.ActiveXObject)
        { 
            alert("activeX");
            for(var i = 6;i;i--)
            { 
                try
                {
                    if( i == 2 )
                    { 
                        xmlHttp = new ActiveXObject( "Microsoft.XMLHTTP" ); 
                    }
                    else
                    { 
                        xmlHttp = new ActiveXObject( "Msxml2.XMLHTTP." + i + ".0" ); 
                    } 
                    xmlHttp.setRequestHeader("Content-Type","text/xml"); 
                    xmlHttp.setRequestHeader("Content-Type","utf-8"); 
                    break;
                }
                catch(e)
                {
                    alert(i);
                    if(i==1){
                    xmlHttp = new XMLHttpRequest(); 
                    }
                }
            }
        }
        else if( window.XMLHttpRequest )
        { 
            xmlHttp = new XMLHttpRequest(); 
            if (xmlHttp.overrideMimeType) 
            {
                xmlHttp.overrideMimeType('text/xml');
            }
        }     if(xmlHttp!=null){
         return xmlHttp;
     }else{
        alert("xmlHttp为空");
     }
出来对话框的顺序居然是,1, ActiveX ,6,5,4,3,2,1 ,然后执行下去了.注释了catch 里 if 的内容,就出来 xmlhttp为空'.

Answer 11

也就是说,这个IE7 也是用 xmlHttp = new XMLHttpRequest(); 来实例化的.

Answer 12

所以2楼的方法 不判断 是IE还有FF 可以,其它判断了的就不行了..

Answer 13

用jquery中的ajax，又简单又方便。也不需要考虑浏览器的兼容性。。