[Javascript] live populate a select box from check boxes

So I have no idea if this is possible, but I’m going to have a bank of hard coded check boxes that I would like to real-time populate a select box somewhere else on the page as they’re checked. I don’t know aaaanything about javascript, but it’s going to be a huge player in this project so I really need to start just jumping in and doing these things. Unfortunately this one isn’t a fancy embellishment but a necessity.

Any help would be great. If there’s a jQuery or MooTools (or other framework) way to do it that would probably be best as I’ll be doing js stuff everywhere and keeping it all on one framework would be best.