Question

I have a script which contains the following piece of code:

(function ($) {
  // ...
})($);

Can anyone explain how to read it?

Answer 1

1. Create an anonymous function
2. Let it take one argument which will be called $
3. Call the function immediately
4. Pass it one argument which is whatever the value of $ is in the outer scope.

If the $ in the outer scope changes (by having a new value assign to it) then the value for $ in the inner scope will be protected from the change (since it is a different variable).

This also provides a clean scope for all other variables declared inside the function (if they use var as they should).