Bind to a Function
<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:s="library://ns.adobe.com/flex/spark"> <mx:CurrencyFormatter id="formatter" precision="2" /> <mx:VBox> <mx:Label text="Enter the withdrawl amount:" /> <mx:TextInput id="amtInput" /> <mx:Label text="Formatted amount:" /> <s:RichText text="{formatter.format( amtInput.text )}" /> </mx:VBox> </mx:Application>