What's the technique that the Google analytics tracking code uses?

Question

The Google Analytics tracking code looks like this:

(function() {
code
  })();

What\'s the technique they are using with those brackets -

Answer 1

The "function(){code}" part only creates a function, the () at the end call the created function. You could rewrite

(function() {
code
  })();

As

var x = function() {code};
x();