In fact I wanted to start my own -- except I don't have a single clue of how to even go about doing something like that. Though now that I think about it, I wish all the effort was put into a single project that wouldn't die off within a few months of going public.
If you want to give something like that a go, then a good place to start is by modifying or adding to an existing compiler. It will give you some exposure to other peoples code too and a good place to start - you'll always have something with tangible results.
Either that or read op on writing interpreters. They can be amazingly simple...
Interestingly, the report mentions that none of the authors knew Javascript before they started.
In fact I wanted to start my own -- except I don't have a single clue of how to even go about doing something like that. Though now that I think about it, I wish all the effort was put into a single project that wouldn't die off within a few months of going public.