Using the ZipCodeFormatter with format
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script> [Bindable] private var storedZipCode:Number=123456789; </mx:Script> <mx:ZipCodeFormatter id="ZipCodeDisplay" formatString="#####-####" /> <mx:TextInput text="{ZipCodeDisplay.format(storedZipCode)}" /> </mx:Application>