Just a quick note: I found recently that some browsers don’t complain when I use future reserved words as identifiers in JavaScript. Specifically, I used char as a variable name, and no Windows browser had a problem with it — but when I tested on Mac, both Safari and Firefox complained. Apparently there are differences in JavaScript implementation between the Windows and Mac versions of Firefox 1.5!
Nitty-gritty details: the ECMA-262 spec defines reserved words and future reserved words in section 7.5.1. Many OO-ish keywords like implements are reserved for the future, as well as specific data types like int and … you guessed it, char.
Confirmed, co-incidentally, with Safari 1.3. Firefox 1.5 had no problem, though.
That’s common practice.