thorough an overhaul as some programmers would have liked, ECMAScript 5 provides important updates that fix common pitfalls from ECMAScript 3 and allow developers to create more secure, robust programs.
Perhaps the most applauded new feature of ECMAScript 5 is native JSON support. In ECMAScript 3, methods to implement JSON data in programs, such as JSONP and json.js, caused security and scalability issues. Mozilla developer John Resig further analyzed the need for native JSON support on his blog. It appears his argument has been heeded. With native JSON support, common security and scalability issues are solved. And while most major browsers implemented native JSON support around the time of the first ECMAScript 5 drafts, the final standardization should eliminate any cross-browser disparities.