Flex dynamic binding

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="/2006/mxml"
    layout="absolute" initialize="init();">

    <mx:Script>
        <!--[CDATA[
            import ;
            import ;

            
            private var watcher1:ChangeWatcher;
            private var watcher2:ChangeWatcher;

            /**
* Dynamic binding
             * @return void
             * **/
            private function Binding():void {

//Bind txtInput with ID txt2
//Binding text with txtInput attribute
//TxtInput with monitor ID txt1
//The monitor's attribute is txtInput text
                watcher1 = (txt2,"text",txt1,"text");

//Binding txtInput with txtComb
//Binding text with txtInput attribute
//ComboBox with monitor ID of comb
//The monitor attribute is the value of ComboBox
                watcher2 = (txtComb,"text",comb,"value");
            }

            /**
* Unbind
             * @return void
             * **/
            private function UnBinding():void {
//Unbind
                ();
                ();
            }        
        ]]-->
    </mx:Script>

    <mx:ApplicationControlBar dock="true">
<mx:Button label="Dynamic Binding" click="Binding();"/>
<mx:Button label="UnBinding();"/>
    </mx:ApplicationControlBar>

    

    <mx:VBox width="200" height="200">

        <mx:Spacer height="30"/>

        <mx:TextInput />
        <mx:TextInput />

        <mx:Spacer height="30"/>

        <mx:ComboBox >
            <mx:dataProvider>
                <mx:Array>
                    <mx:String>Beijing</mx:String>
                    <mx:String>Shanghai</mx:String>
                    <mx:String>Hangzhou</mx:String>
                </mx:Array>
            </mx:dataProvider>
        </mx:ComboBox>

        <mx:TextInput />
        </mx:VBox>
</mx:Application>