Why i can't save the return value of XMLHTTPRequest in a variable?

[web.designer.iq]

Hi
This code is working perfectly:
XMLHttpRequestObject.onreadystatechange = function()
{
if ( XMLHttpRequestObject.readyState == 4 && XMLHttpRequestObject.status == 200 ) {
obj.innerHTML = XMLHttpRequestObject.responseText;
}
}

But i need to store the responseText value in a variable like this:
var resText = XMLHttpRequestObject.responseText;
any idea please?

[bpat1434]

that should work perfectly fine. It's the way I do it.