ajax not working in Firefox 2

[frank1]

well we were using this function in our most ajax file

function GetXmlHttpObject()
{
var xmlHttp4=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp4=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp4=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp4=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
return xmlHttp4;
}

it was working fine with all IE 6 and 7 and FF 1.5
Now we are using Firefox 2.0.0 ...
and all ajax has stopped working...no error
we have zend studio...error console...firefox extension...it also shows no errors...but ajax action are not evoked..
for eg onchange=showform()

but when we do nothing happens

please help

[Mittineague]

new XMLHttpRequest() works for me in Firefox 2
Do you have an extension installed that's causing problems?

Maybe try

function GetXmlHttpObject()
{
var xmlHttp4=null;
try
 {
 // Firefox, Opera 8.0+, Safari
 xmlHttp4=new XMLHttpRequest();
 }
catch (e)
 {
 //Internet Explorer
 try
  {
  xmlHttp4=new ActiveXObject("Msxml2.XMLHTTP");
  }
 catch (e)
  {
  xmlHttp4=new ActiveXObject("Microsoft.XMLHTTP");
  }
 }
alert(xmlHttp4);
return xmlHttp4;
}

and see if the alert says "object"