Spinner doesn't update it's value in ipad

<vlayout>
	<label multiline="true">
	1. in ipad.
	2. click spinner's button to increase value.
	3. click on the button, you should see a alert which shows the last the value of spinner
	</label>
	
	<spinner id="s"/>
	<button label="get spinner value" onClick='alert("Spinner value : "+ s.getValue())'/>

</vlayout>