Xenakis' Sieves with JavaScript

So I'm trying to learn about JavaScript and using it in Max, but I'm still at real early stages working with code. I've tried to write a little script that generates elementary Sieves (see Iannis Xenakis & Christopher Ariza). Like I say, its a real rudimentary (and yeah, its probably easier to combine the residual classes using Max [zl] processes, but this is a learning exercise for [js]) so don't expect the full complement of sieve handling methods that people like Ariza have done.

I'm encountering a bit of a weird problem getting the segment to work starting from a negative number. I'm thinking that its because the Sieves should start at 0 and run simultaneously in either direction 'infinitely' - the segment should just be a frame, but maybe i'm using it as a point of initialised?

I've only been learning JavaScript for about 2 weeks through codeAcademy.com - and then only just looked at using [js] to implement it through Max - so I'm assuming there will be some real basic errors?

If anyone could take a look and give me some pointers on areas for improvement, it'd be really appreciated!