Need Help With disabling backspace key to prevent the previous page from loading in FLEX

Question

    <mx:Label text="SAVIO"/>
    <mx:ComboBox focusEnabled="true"></mx:ComboBox>
    <mx:Button label="Button" focusEnabled="true"/>
    <mx:Script>
            <![CDATA[
                import mx.controls.Alert;
                private var t:TextField;
                    private function init():void
                    {
                         t=new TextField();
                         nom.setFocus();
                            addEventListener( KeyboardEvent.KEY_UP,xxx);
                            addEventListener( KeyboardEvent.KEY_DOWN,xxx);
                    } 

                    private function xxx( event:KeyboardEvent ):void
                    {
                            if( event.type == KeyboardEvent.KEY_DOWN && event.ctrlKey )
                             setFocus();
                            else nom.setFocus();
                            nom.selectionEndIndex = nom.selectionBeginIndex = nom.text.length;

        if (event.target == t && event.keyCode == 8)    //Here is the problem Please Help..
        {

        }
                    }


            ]]>
    </mx:Script>

Answer 1

e.keyCode = Keyboard.ESCAPE is usefull