To create the simplest flash loader we have to know only two functions:

getBytesTotal() - this function gives back  total  size of clip;

getBytesLoaded()  - this function gives back a quantity of bytes of each flash clip.

Flash Loader Example:

1. We create a clip that must has a minimum weight. Put it into the first frame. Let's give it the name: startclip In the same frame stop clip by using stop()

2.  Inside a clip in the first frame we create text area to show percents. the name of variable will be calle: procent

3. use the following ActionScript on the clip:

onClipEvent (load) {
fullsize = _root.getBytesTotal();
}

onClipEvent (enterFrame) {

nowsize = _root.getBytesLoaded();
otnoshenie = nowsize/fullsize*100;
_root.startclip.procent = Math.floor(otnoshenie);
if (nowsize == fullsize) {_root.gotoAndStop(2);
}
}

4. the loader is ready :)