Get Combo value

I was thinking that get the combo value is really simple…but i have i problem, this is the code:

<script>
        var z=new dhtmlXCombo("combo_zone2","",230);
		z.enableFilteringMode(true,"system/Polizza_Search.php",false);
		z.attachEvent("onChange", onChangeFunc);
		function onChangeFunc() {
			dhxLayout1.cells('b').attachURL('test111.php?ID=' + z.getSelectedValue());
		}
	</script>

and this a part of the XML that is loaded in the combo:

<?xml version="1.0" encoding="iso-8859-1" ?> 
- <complete>
- <option value="1">
- <![CDATA[ 0.037.161
  ]]> 
  </option>
- <option value="2">
- <![CDATA[ 0.042.845
  ]]> 
  </option>

And this is the adress that is outputted: 192.168.1.77/V3.0/test111.php?ID=null

The output value is: Null :frowning:

OK i was having 2 combo with the same name (z)…sorry :wink: