That is an outstanding explanation, thanks!
Michael Geary wrote:
From: Leandro Vieira Pinho (function(){ ... })(); I would like to know, what´s the name of that sintax.From: Josh Nathanson Is that a closure?Not exactly. One common use of the "anonymous function called in place" is to create a closure, but this itself isn't a closure. For example: (function() { var message = 'hello'; function test() { alert(message); } test(); })(); test(); // fails There's no closure here, because there are no references outside the function to any of the function's local variables or local functions. However, there is a local scope, so the call to test() outside the anonymous function will fail (as expected). var test1; (function() { var message = 'hello'; function test() { alert(message); } test(); test1 = test; })(); test1(); // succeeds test(); // fails Almost the same thing, but the "test1 = test;" statement creates a reference to the test function *outside* the anonymous function. Now we have a closure, where variables local to the function are preserved for later use outside the function. Basically, every function call creates a local scope. If the function creates any references to its local variables or functions that are outside the function, then a closure is created to save those variables. The closure remains in existence as long as any of those references are kept. This is true for named functions as well as anonymous functions - there's no difference between the two. People do often refer to a local scope as a closure, but it's not really correct - a closure refers specifically to the situation where local variables and local functions outlive the function call in which they were created. -Mike
