Loaded movies control

1

I loaded a movie “A” into a _placeholder by pressing a button. When that movie gets to the end (frame 5), it should automaticlaly unload and load movie “B” in the same _placeholder. Specifically, how do I address the movie “A”?

so far:

_button.onRelease = function () {
_placeHolder.loadMovie(“A.swf”, 1);
}

if ((_placeHolder._currentframe) ==5) {
unloadMovie (_placeHolder);
_placeHolder.loadMovie(“B.swf”,1);
}