Last year I wrote A brief introduction to closures which was meant to help people understand exactly what a closure is and how it works. I’m going to attempt that again, but from a different angle. I think with these kinds of concept, you just need to read as many alternative explanations as you can in order to get a well rounded view.
Standard ECMA-262 ECMAScript® Language Specification Edition 5.1 (June 2011) This Standard defines the ECMAScript scripting language. The following file can be freely downloaded: