Private variables in JavaScript

gistfile1.js

console.log("Private variables in JavaScript");

var a =		(function(){
				return obj = {
					pub : 'public data',
					getSecret : function() {
						var secret = 'my secret';
						return secret;
					}
				};
			})();

console.log("The object (No reference to private data) : ");
console.log(a);
console.log("Private data retrived with get functions : ");
console.log(a.getSecret());