Brendan Eich Explains ECMAScript 3.1 To Developers
VonGuard writes "On April 9, ECMA International produced the final draft for the first major update to JavaScript since 1999. It's called ECMAScript 3.1, but will soon be known as ECMAScript, Fifth Edition. You'll know it as JavaScript, the Next Generation. Mozilla will begin implementing these features after Firefox 3.5, and Microsoft is already showing prototypes behind closed doors. The question, however, is what this will change for JavaScript coders. To get those answers, I tracked down Brendan Eich, Mozilla's CTO and the creator of JavaScript. I transcribed the interview without any editorial since he explains, perfectly, what's changing for programmers. Long story short: Json will be safer, getters and setters will be standard, and strict mode will make things easier to debug."
ECMAScript is a prototypal functional programming language. You don't just set members of an object by defining its prototype in an object literal.
You can also, by the power of closures, have private functions, private variables, and protected functions. (ECMAScript is interesting in that public member functions cannot access private variables, but protected functions can. Downside is that protected functions (defining them as this.foo = function() {}; in the constructor) are created new for each instance of the object, unlike the prototype (public) members.
While ECMAScript isn't built to enhance tail recursion, it's actually possible. For example, a continuous passing style fibonacci sequence calculator.
Not quite as readable as haskell or lisp, but still - proves that JavaScript is a true functional programming language.