Strands is a language written in JS; the language is javascript itself except with concurrency primitives added: http://www.xucia.com/strands-doc/index.html htt

Strands is a language written in JS; the language is javascript itself except with concurrency primitives added: http://www.xucia.com/strands-doc/index.html http://www.xucia.com/strands-doc/index.html I mention strands to say that you could do something similar: by using narcissus (a js interptreter written in js - http://mxr.mozilla.org/mozilla/source/js/narcissus/ http://mxr.mozilla.org/mozilla/source/js/narcissus/) you could interpret a language that was a subset of javascript, with whatever restrictions you wanted. Though javascript's extremely dynamic nature would possibly make this challenging. More pragmatically, lethain's right that you should look into caja.