Declare variables referenced in enterframe at function or class level?

Hi,

If i have a series of variables that are referenced on an enter frame function, is it better to declare the frequently used vars at the class level? Is there a performance benefit? What is the standard?

Example

PHP Code:

---


public class Animation extends Sprite{

  private var num:int;

  public function Animation(){
  }

  private function happensOnEnterFrame():void{
    num = transformation
    // do other things with num...
  }

} 


---

...as opposed to...

PHP Code:

---


public class Animation extends Sprite{

  public function Animation(){
  }

  private function happensOnEnterFrame():void{
    var num:int
    num = transformation
    // do other things with num...
  }

} 


---

Personally, unless num needs to be used outside of that function, I would declare it inside. Why clutter up the class with properties that are used in only a single place?

I haven't tested, but I would also expect the local variable to be slightly faster as it's in a narrower (and thus resolved earlier) scope.

Thanks flax, I thought that perhaps if the variable was only declared only once at the class level instead of being redeclared every time the enterFrame function was called, there might be a performance benefit although likely infinitesimal. The points about cluttering the class and possible speed benefit due to local scope make sense.