AJAX does not work without an alert

Instead of an id getting its innerHTML changed, the entire page is getting refreshed with this function of mine (you may want to look just at the end of the function where there's an alert):

function morerating(ratingform, checkflag, loc)
{
	var f = document.forms[ratingform];
	var rating_done_flag = 0;
	var params = "";
	if (checkflag == true)
		check = checkrating(ratingform);
	else 
		check = true;
	if(check == true)
	{
		f.submit_rating_done.value = "";
		for (i=0;i < f.elements.length;i++) { 
			if(f.elements[i].type == 'radio' || f.elements[i].type == 'checkbox')
			{
				if(f.elements[i].checked)
				{
					params = params + f.elements[i].name +'='+ encodeURI(f.elements[i].value) + '&'; 
					if (f.elements[i].name == "rating_1" || f.elements[i].name == "rating_2" || f.elements[i].name == "rating_3" || f.elements[i].name == "rating_4" || f.elements[i].name == "rating_overall")
						rating_done_flag = 1;
				}
			}
			else if (f.elements[i].name && f.elements[i].value)
			{
				params = params + f.elements[i].name +'='+ encodeURI(f.elements[i].value) + '&';
			}
		}
		shows = loc;
		xmlHttp=GetXmlHttpObject();
		if (xmlHttp==null)
		{
			alert ("Browser does not support HTTP Request");
			return;
		}
		if(document.getElementById('morehide'))
		{
			document.getElementById('morehide').style.display = "none";
			document.getElementById('morehide').innerHTML = "";
		}
		if(shows == "rating_main_block" || shows == "rating_main_block_editorial" || shows == "loginbox" || shows == "editorial_loginbox")
		{
			params = params + "submit_rating_done=1&";
			params = params + "xmlrequest=1&";
		}
		else
		{
			if(!document.getElementById('morehide'))
			{
				f.submit_rating_done.value = "Submit";
			}
		}
		params = params + "shows="+shows;
		var url='/blocks/profiles/common/user_store.php';
		url=url + "?" + params;
		xmlHttp.onreadystatechange=stateChangedALL;
		xmlHttp.open("GET",url,true);
		xmlHttp.send(null);
		//setTimeout('window.scrollBy(0, 350)', 1000);
		//alert('help2');
		return true;
	}
	else
	{
		return false;
	}
}

Code (markup):

That alert('help2'), if removed, causes the page to just reload, but with it, AJAX works fine. I tried some dummy setTimeout option also as you can see, but that doesn't seem to help either. I also tried setTimeout("alert('help2')", 1000).

If it helps, these are the other functions referred to there, though they're pretty standard AJAX stuff:

function stateChangedALL()
{
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
	{
			document.getElementById(shows).style.display="block"
			if (xmlHttp.responseText != "")
				document.getElementById(shows).innerHTML=xmlHttp.responseText
			else
				document.getElementById(shows).style.display="none"
			var the_node = document.getElementById(shows);
			execJS(the_node);
			if(document.getElementById(trashid))
			{
				xmlHttp2.send(null);
			}
	}
	else
	{
			document.getElementById(shows).innerHTML="<br><br><div class=\"a9bl\" align=\"center\"><font color=black>Loading, please wait...</font><div>"
	}
}

Code (markup):

and

function GetXmlHttpObject()
{ 
    var req = false;
    // branch for native XMLHttpRequest object
    if(window.XMLHttpRequest && !(window.ActiveXObject)) 
	{
		try {
			req = new XMLHttpRequest();
        } catch(e) {
			req = false;
        }
    // branch for IE/Windows ActiveX version
    }
	else if(window.ActiveXObject) 
	{
       	try {
        	req = new ActiveXObject("Msxml2.XMLHTTP");
      	} catch(e) {
        	try {
          		req = new ActiveXObject("Microsoft.XMLHTTP");
        	} catch(e) {
          		req = false;
        	}
		}
    }
	return req
}

Code (markup):

I'd be quite grateful for any pointers! Thank you for your time!

 

Writing your own ajax handlers is like making a wheel with bamboo.. bit dodgy.
I recommend jQuery.com's ajax routines (15kb, free).

 

But to tell you something about the code you're using now; it's probably a timing issue between the return-handler and the rest of your code, that calls morerating(). something else is likely depending on the result (when caught by stateChangedALL()). the alert ensures that you spend more than 1 second, and that's enough time for the ajax call to complete.
if this is the case, then the solution is to set a global var busy=true, and have the rest of your code check for that var being set to false (by stateChangedAll()).

 

Okay, I got it - I was returning true when I should have been returning false. So this was the issue:

function morerating(ratingform, checkflag, loc)
{
                //some code...
		xmlHttp.onreadystatechange=stateChangedALL;
		xmlHttp.open("GET",url,true);
		xmlHttp.send(null);
		[COLOR="Red"]return false[/COLOR]; /*this was "true" earlier*/
	}
	else
	{
		return false;
	}
}

Code (markup):

Still, though, why was the alert making it work?