Why doesn't this FOR loop work!?

I am using some code from one of the Kirupa random movie tutorials to load a random movie upon loading a page…problem is, I want it to continuously cycle through a number of movie clips (according to variable ‘i’).

This is the code example:

 filename = ["fuji.swf", "calient.swf"];
i = filename.length;
k = Math.floor(Math.random()*i);
for (i=0; i <= 3;) {
loadMovie(filename[k], movieTarget);

Anyone have any clues? One of the movies stops upon reaching the end of its timeline, the other one will continuously loop.