Problem running AJAX properly on IE6 and IE7

Question

I have this code, which is working fine in FireFox, chrome and IE8 but is it not working on IE6 and IE7.

function GetXmlHttpObject() {
  //var xmlHttp = null;
  try {
    xmlHttp = new XMLHttpRequest();
  } catch (e) {
    try {
      xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
  }
  return xmlHttp;
}

function login()
{
    alert("Entered Login()"); 
    var url="http://server.com/ALUauth.php";
    xmlhttp.onreadystatechange=statechangedLogin;
    xmlhttp.open("GET", url, true);
    xmlhttp.send(null);
}

function statechangedLogin()
{
    if(xmlhttp.readyState==4)
    {
     alert("Entered State Changed Login");
     if (xmlhttp.responseText=="Please <a href=http://server.com/ALUauth.php?login&gt;login&lt;/a&gt;")
     {
      document.getElementById("ALUauth").innerHTML=xmlhttp.responseText;
     }
     else
     {
      GetEmailId();
     }

    }
}

function GetEmailId()
{   
    alert("Entered GetEmailId()");
    var url="http://server.com/GetPostEmail.php";
    url=url+"&sid="+Math.random();
    xmlhttp.onreadystatechange=statechangedLogin2;
    xmlhttp.open("GET", url, true);
    xmlhttp.send(null);
}

function statechangedLogin2()
{ 
    if(xmlhttp.readyState==4)
    {
        alert("Enter State Changed Login 2");
        if(xmlhttp.responseText=="Login again")
        {
                window.location="http://server.com/profile.html";
        }
    }
}

When I run the code in any other browser except for IE6 and 7 the output shows me all the alert boxes starting from: - Entered Login() - Entered State Changed Login - Entered GetEmailId() - Enter State Changed Login 2

and then the window location changes to http://server.com/profile.html

but when I run the same thing on IE 6 or 7, the code does not go into the statechangedLogin2(), and so the only alerts I get here are:

• Entered Login()
• Entered State Changed Login
• Entered GetEmailId()

I am unable to figure out why this issue is occuring. Why is it happening, and what should I change? The project is working absolutely fine on other browsers include IE8.

Can some one help me figure this issue of mine.

Answer 1

It's hard to read your code since it isn't formatted but I think your problem is that you're turning xmlhttp into a global variable rather than passing it around (I think...).

Try changing your xmlhttp.onreadystatechange to read

xmlhttp.onreadystatechange = function() { statechangedLogin(xmlhttp); };

and

xmlhttp.onreadystatechange = function() { statechangedLogin2(xmlhttp); };

and then change your functions for statechangedLogin and Login2 to accept the parameter

function statechangedLogin(xmlhttp) {
  // ... code here
}

The problem could be that you're accidentally overwriting the current request in the xmlhttp variable before it's finished which could cause those events not to fire. By making xmlhttp a local variable per function you can call those functions multiple times and they won't overwrite or stop each other.

Answer 2

Hello i am sorry to post my question again. but i was not getting any solution there so i tried to do this. thou i am sorry about it.

Anyways i was able to solve the situation with the help of my boss.

all i did was to give GetEmailId function its own session. something like this:

function GetEmailId()   
 { 
 alert("Entered GetEmailId()"); 
 xmlhttpTwo=GetXmlHttpObject();
 var url="http://server.com/GetPostEmail.php";
 url=url+"&sid="+Math.random();
 xmlhttpTwo.onreadystatechange=statechangedLogin2;
 xmlhttpTwo.open("GET", url, true);
 xmlhttpTwo.send(null);
 }

I tried this and it works absolutely fine on IE 6 n 7 ... :)

Best Zeeshan