function foo2() { return { bar: "hello" }; }

Throws error on invalid usage of delete. The delete operator (used to remove properties from objects) cannot be used on non-configurable properties of the object. Non-strict code will fail silently when an attempt is made to delete a non-configurable property, whereas strict mode will throw an error in such a case.

Disallows duplicate property names or parameter values.

Prevents accidental globals. Without strict mode, assigning a value to an undeclared variable automatically creates a global variable with that name. This is one of the most common errors in JavaScript. In strict mode, attempting to do so throws an error.

A client-side Javascript SDK for authenticating with OAuth2 (and OAuth1 with a oauth proxy) web services and querying their REST API's. HelloJS standardizes paths and responses to common API's like Google Data Services, Facebook Graph and Windows Live Connect. It's modular, so that list is growing. No more spaghetti code!

javascript web applications and elasticsearch

Developers these days are spoiled with choice when it comes to selecting an MV* framework for structuring and organizing their JavaScript web apps.

Rich JavaScript Applications – the Seven Frameworks (Throne of JS, 2012)