What does it mean whenever a function ends with })(jQuery);?

Question

I tried googleing, but Google doesn't seem to care about parentheses...

Answer 1

If you see this:

(function($) {
    // ...code using $...
})(jQuery);

It's doing two things:

1. Defining an anonymous function that uses $ as its reference to jQuery.
2. Calling it, passing in jQuery.

You could do it like this:

function foo($) {
    // ...code using $...
}
foo(jQuery);

...but that creates an unnecessary symbol.

All of this is because jQuery has the symbol jQuery and the symbol $, but it's not uncommon for people to use jQuery.noConflict() to tell jQuery to return $ back to whatever it was when jQuery loaded, because a couple of other popular libraries (Prototype and MooTools, to name two) use $ and this lets someone use those libraries and jQuery together. But you can still use $ within your function, because the argument shadows whatever that symbol means outside the function.

Answer 2

It basically automatically invokes the anonymous/lambda function defined and supplies the jQuery reference to it.

Pretty much the same as functionCall(jQuery) except you define it and invoke it in the same line/expression.