keystroke in list

<?page title="new page title" contentType="text/html;charset=UTF-8"?>
<zk xmlns:w="http://www.zkoss.org/2005/zk/client">

	<script type="text/javascript" defer="true"><![CDATA[ 
	
		function detectKey(e) {
		
			var evtobj=window.event? event : e
			var unicode=evtobj.charCode? evtobj.charCode : evtobj.keyCode
			var actualkey=String.fromCharCode(unicode)

			zAu.send(new zk.Event(zk.Widget.$("$winDetector"), "onUser", actualkey))
		}
		
		document.onkeypress = detectKey
	]]></script>
	
	<zscript><![CDATA[
	                  
		List items = new ArrayList(50);
		for (int i = 0; i<100; i++) {
			items.add("" + i);
		}
	
	]]></zscript>
	

	<window id="winDetector">
	
		<attribute name="onUser"><![CDATA[
			for (int index = 0; index<50; index++) {
				String s = items.get(index);
				if (s.startsWith((String)event.getData())) {
					listbox.setSelectedIndex(index);
					break;
				}
			}
			]]>
		</attribute>

		<listbox id="listbox" height="150px" fixedLayout="true">
	             <listitem forEach="${items}">
	                  <listcell label="${each}" />
	             </listitem>
	        </listbox>
	    		
    </window>
</zk>