Synchronize TextInput and TextArea with data binding
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Script> [Bindable] private var bindableText:String = ""; </mx:Script> <mx:VBox> <mx:TextInput id="input" /> <mx:TextArea text="{input.text}" id="area" height="{(Math.round(input.text.length/40)+1) * 20}" wordWrap="true"/> </mx:VBox> </mx:Application>