convert onEnterFrame Event Handler AS2 code into AS3

this.addEventListener(Event.ENTER_FRAME,onEf);

// "this" references the movie itself, you can also use "stage" or the instance name of an object on the stage

// look up addEventListener in the online help. This method takes two arguments, the event that you want to "listen" for and the name of the function to execute when the event occurs.

// the function that will be called when the event occurs. It takes one argument that corresponds with the first argument of the addEventListener method.

function onEf(event:Event):void {

}

objectName.addEventListener(Event.ENTER_FRAME, Handler);

function Handler(evt:Event):void {

     ...

}