Why do many javascript libraries begin with “(function () {”?

Question

Why do many javascript libraries look like this:

(function () { 
    /* code goes here */ 
})();

It appears to define an unnamed function whic

Answer 1

JavaScript doesn't have block scoping, only function scoping. By creating and immediately invoking an anonymous function, we can guarantee that its local variables won't step all over the global namespace. It's basically a way to limit conflicts with other libraries that may be in play.