XMLHttpRequest. onreadystatecha nge Method Not Running

[HugeBob]

Hi All,

I'm having a problem with a web app I'm writing. I have a form for
which I'm going to validate one of the fields. I use AJAX to retrieve
XML containing a list of valid entries. My app works under IE, oddly
enough. But, under Firefox, it seems that the
XMLHttpRequest. onreadystatecha nge method is not being called. The
code follows. I'm using synchronous mode because I'm thinking that I
want that global variable g_groupListXML to contain
xmlHttp.respons eText before ajaxGetGroupUse rListXML( ) returns. Am I
right on this point?

function getXMLHTTPReque stObject( )
{
var xmlHttp = null;
try
{
// Firefox, Opera 8.0+, Safari
xmlHttp = new XMLHttpRequest( );
}
catch (e)
{
// Internet Explorer
try
{
xmlHttp = new ActiveXObject(" Msxml2.XMLHTTP" );
}
catch (e)
{
try
{
xmlHttp = new ActiveXObject(" Microsoft.XMLHT TP");
}
catch (e)
{
alert("Your browser does not support AJAX!");
}
}
}
return xmlHttp;
}
var g_groupListXML = null;

function ajaxGetGroupUse rListXML(url)
{
var xmlHttp = null;
xmlHttp = getXMLHTTPReque stObject( );
xmlHttp.onready statechange = function ()
{
if
(xmlHttp.readyS tate == 4)
{

alert("onreadys tatechange called...");

g_groupListXML = xmlHttp.respons eText;
}
}
xmlHttp.open("G ET", url, false);
xmlHttp.send(nu ll);
}

function getGroupListXML (form)
{
var retval = false;
var xmlDoc = null;
var doc = null;

ajaxGetGroupUse rListXML('XMLPr oducingScript.c fm');

// Parse retrieved XML
if (window.ActiveX Object)
{
doc = new ActiveXObject(" Microsoft.XMLDO M");
doc.async = "false";
doc.loadXML(g_g roupListXML);
}
else
{
var parser = new DOMParser( );
doc = parser.parseFro mString(g_group ListXML, "text/xml");
}

xmlDoc = doc.documentEle ment;
form.fieldx.val ue = trim(form.field x.value);

for (var i = 0; i < xmlDoc.childNod es.length; i++)
{
if (xmlDoc.childNo des[i].childNodes[0].nodeValue.toLo wer( ) ==
form.group_name .value.toLowerC ase())
{
alert('String already used');
retval = true;
break;
}
}
return retval;
}

[HugeBob]

Hi All,

Problem solved!! With the aid of Firebug (God bless the makers of
Firebug!!!), I was
able to determine that the global variable set by the
onreadystatecha nge handler wasn't being set at all. I think there
must be a scope issue with that global variable. At least in Firefox
and Netscape anyway. Firebug showed me that responseText was clearly
populated with the data I expected. Firefox seems to have been
differentiating between the global g_groupListXML and the local one in
the handler.

var g_groupListXML = null;
function ajaxGetGroupUse rListXML(url)
{
var xmlHttp = null;
xmlHttp = getXMLHTTPReque stObject( );
xmlHttp.onready statechange = function ()
{
if (xmlHttp.readyS tate ==
4)
{
g_groupListXML =
xmlHttp.respons eText;
}
};
xmlHttp.open("G ET", url, false);
xmlHttp.send(nu ll);
}