Underline text in button on mouse over

Simple application to underline the text when mouseover on the button

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical">

<mx:Button id="btn" label="Mouse Over" 

mouseOver="btn.setStyle('textDecoration','underline')"

mouseOut="btn.setStyle('textDecoration','none')"

labelPlacement="left" useHandCursor="true"

buttonMode="true"/>

</mx:Application>