Transparent GIF animation?

Well, I wrote a thread in the "Adobe PhotoShop" section for not too long ago. Where I aimed on how I can save an transparent GIF animation (with no background), which turns out that I actually can't (well, it's like hidden and just pisses me off the more I try, spent the whole evening on this and still no solution).

So this thread is more aiming outside any photoshop that seem not to be able to handle simple stuffs, or atleast make simple stuffs hard to find and perform.

TO THE DEAL:

I made some beautiful white stars using trapcode particular in After Effects, with no background.
Now I want this to make a transparent GIF animations, so I can add this GIF animation to a blue background for example (I'll be using it in a website with HTML), and there will remain blue background while the white stars are above and that has same smoothness as they're in After Effects.

So, what's the way? Any recommendations of rendering settings in AE or any other software I shall be using?

Thanks in advance
So what can I do to make this work?