Issue In INTBOX with IE Browser

<?xml version="1.0" encoding="UTF-8"?>
<?taglib uri="http://www.zkoss.org/dsp/web/core" prefix="c"?>
 

<zk xmlns="http://www.zkoss.org/2005/zul"
	xmlns:h="http://www.w3.org/1999/xhtml"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.zkoss.org/2005/zul http://www.zkoss.org/2005/zul/zul.xsd">
 
	<grid>
		<columns>
			<column width="150px" />
			<column />
		</columns>
		<rows>

			<row visible="true">
				<label value="intbox 1" />
				<hbox>
					<intbox id="intbox1" maxlength="1">
						<attribute name="onBlur">
							changeProperty(intbox2);
						</attribute>
					</intbox>
				</hbox>
			</row>
			<row visible="true">
				<label value="Intbox 2" />
				<hbox>
					<intbox id="intbox2" maxlength="5"
						readonly="true">
					</intbox>
				</hbox>
			</row>


		</rows>
	</grid>

	<zscript>
	void changeProperty(Intbox intbox2) {
		intbox2.setReadonly(false);
		intbox2.setText("0");
	}
</zscript>

</zk>