Functions and doing things per frame

Okay… I have this actionscript:

 onClipEvent(enterFrame){
 var select = function(number) {
  var goto = number * 28 + 70
  if(this._y != goto){
  this._y += (goto-this._y)/3 + 1}}
}
on (release){
 select(3)} 

It is to make this button go down quickly and the go slower until it stops. However, my problem is that when I press it, it does just one frame of what I want it to do, and I must click it many more times to get it to work… so how do I get it to do it each time a frame goes by?