ZK allows developers to handle events at the client side.

In this example, the onFocus and onBlur events triggered in the textbox are handled at the client, invoking the appearing/disappearing of texts using a jQuery effect.

<grid  xmlns:c="client">
    <rows>
        <row>
            <label value="text1: " />
            <textbox
            	c:onFocus="jq(this.$f('help1')).fadeIn()"
				c:onBlur="jq(this.$f('help1')).fadeOut()"/>
            <label id="help1" visible="false"
				value="This is help for text1." />
        </row>
        <row>
            <label value="text2: " />
            <textbox
            	c:onFocus="jq(this.$f('help2')).fadeIn()"
				c:onBlur="jq(this.$f('help2')).fadeOut()"/>
            <label id="help2" visible="false"
				value="This is help for text2." />
        </row>
    </rows>
</grid>