[HELP] jQuery widget ZK5.0.2

<?page title="Auto Generated index.zul"?>
<zk>
	<window title="Hello World!!" border="normal" width="200px" apply="test.IndexCtrl">
	<panel>
		<panelchildren>
	<script type="text/javascript"> <![CDATA[
			function showError(widget, msg) {
			var html = "<div ><span>*"+ msg +"</span></div>";
			jq(widget[widget.length-1]).after(html);
			console.log(widget);
		}
	]]>
	</script>
			<button id="btnShow" label="Show Window" />
		</panelchildren>
	</panel>
	</window>
</zk>

package test;

import org.zkoss.zk.ui.Executions;
import org.zkoss.zk.ui.SuspendNotAllowedException;
import org.zkoss.zk.ui.util.Clients;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Window;

public class IndexCtrl extends GenericForwardComposer {

	/**
	 * 
	 */
	private static final long serialVersionUID = -9200331251694400936L;

	public void onClick$btnShow() {
		try {
			Window winForm = (Window) Executions.getCurrent().createComponents(
					"/window.zul",
					null, null);
			winForm.invalidate();
			winForm.doModal();
			winForm.detach();
			winForm=null;
		} catch (SuspendNotAllowedException e) {
			Clients.clearBusy();
			e.printStackTrace();
		} catch (InterruptedException e) {
			Clients.clearBusy();
			e.printStackTrace();
		} catch (Exception e) {
			Clients.clearBusy();
			e.printStackTrace();
		}
	}
}

<?page title="new page title" contentType="text/html;charset=UTF-8"?>
<zk>
<window id="windowForm" title="new page title" width="400px" border="normal" apply="test.WindowCtrl">
	<grid>
		<columns>
			<column width="20%" />
			<column />
		</columns>
		<rows>
			<row>
				<label value="Firstname" />
				<textbox id="txtFirstName" width="99%" />
			</row>
			<row>
				<label value="Latname" />
				<textbox id="txtLastName" width="99%" />
			</row>
			<row>
				<button id="btnOk" label="OK" />
				<button id="btnCancel" label="Cancel" />
			</row>
		</rows>
	</grid>
</window>
</zk>

package test;

import org.zkoss.zk.ui.Component;
import org.zkoss.zk.ui.util.Clients;
import org.zkoss.zk.ui.util.GenericForwardComposer;
import org.zkoss.zul.Textbox;
import org.zkoss.zul.Window;

public class WindowCtrl extends GenericForwardComposer {
	private static final long serialVersionUID = -1374098330647731875L;
	private Window	windowForm;
	private Textbox txtFirstName;
	private Textbox	txtLastName;
	
	public void doAfterCompose(Component comp) throws Exception {
		super.doAfterCompose(comp);
		
		windowForm.setTitle("Please enter your name");
	}
	
	public void onClick$btnOk() {
		String msg = "";
		if(txtFirstName.getText().trim().length()==0) {
			msg += " showError(jq('$txtFirstName'), 'Firstname is mandatory.');";
		}
		
		if(txtLastName.getText().trim().length()==0) {
			msg += " showError(jq('$txtLastName'), 'Lastname is mandatory.');";
		}
		
		if(msg.trim().length()>0) {
			Clients.evalJavaScript(msg);
		} else {
			Clients.evalJavaScript("alert('Hello " + txtFirstName.getText().trim() + " " + txtLastName.getText().trim() + "');");
			windowForm.detach();
		}
		System.out.println(msg);
	}
	
	public void onClick$btnCancel() {
		windowForm.detach();
	}
}

[null, null, input#z_d__c1.z-textbox]
[null, null, input#z_d__f1.z-textbox]

jq(widget[widget.length-1])

jq(widget)