Sizing the movieclip

I am very new to actionscript so if this is a dumb question sorry.

I am messing around to learn more about actionscript and I am trying to have a square movieclip resize itself so both sides are equal to 50
here is my code on the movieclip
it does the resize and all but it keeps on going. I am not sure how to stop it.

this.onLoad = function() {
this._height = 6;
this._width = 6;


this.onEnterFrame = function() {
if(this._currentframe == 50)



any help would be great
thank you