Performance (onEnterFrame)

…I was trying to make this in one other post, but I was going to messy, so new post with all the code I’m using, since I got a way to put it all in one frame…here it goes
[AS]myString = new String(“this is my text”);
i = myString.length;
onEnterFrame = function () {
if (i>0) {
myString_print = myString.substring(i-1, myString.length);
textBox.text = myString_print;
scroll1._visible = (textBox.maxscroll>1);

How can I create a condition to delete this onEnterFrame at the proper moment?