Cant set hidden field to jquery result value, please help

I have been losing hair on this one, never mind sleep !!!

I have a jquery script with 3 drop down boxes 1 ) province 2 ) city 3 ) suburb, when you select #1, the cities load, when you select a city, the suburbs load,
all is working 100%, but the problem is, when I try to save the city value via php $_POST, the value is empty, I have gone as far as trying to enter the returned value
into a hidden field to be submitted with the rest of the form, but to no avail.

I have an alert which does successfully return the value in the alert box, but applying it to a hidden field, stays empty!

please help me out, still very new to javascript & jquery.

the code is below :

the jqeury that returns the city values :

	function getCity(countryId,stateId) {		
		$myvalue = document.getElementById('cities').value;
	    document.getElementById('mycitynew').value = $myvalue; //(document.getElementById('cities').value);
		alert(document.getElementById('cities').value); // test to see if value is there !

		var strURL="findCity2.php?country="+countryId+"&state="+stateId;
		var req = getXMLHTTP();
		if (req) {
			req.onreadystatechange = function() {
				if (req.readyState == 4) {
					// only if "OK"
					if (req.status == 200) {						
						document.getElementById('mycitynew').value = $myvalue;
					} else {
						alert("There was a problem while using XMLHTTP:\
" + req.statusText);
			}"GET", strURL, true);

above you will see I try to enter the jquery value of cities into the hidden field ‘mycitynew’, the alert works, but the value of hidden field stays empty.

my hidden field ( that stays empty, no matter what I try! )

 <input type="hidden" id="mycitynew" name="mycitynew" value=""/>

hi guys,

Got it working!! instead of using a hidden field, I opted for a textbox with style set to display:none, works like a charm!

Hi there,

Glad you got it working, but using a hidden input or a text input (which is then hidden) shouldn’t make a difference.

Hiding a normal text input is a bit hacky.

If you can provide the HTML and the relevant JS, I’d be happy to have a look at it for you.