What is the role of parentheses in the following code snippet?

Question

This is the tracking code for Google Analytics:

var _gaq = _gaq || [];
_gaq.push(["_setAccount", "UA-256257-21"]);
_gaq.push(["_trackPageview"]);

(function() {
var ga = document.createElement("script"); ga.type = "text/javascript"; ga.async = true;
ga.src = ("https:" == document.location.protocol ? "https://ssl" : "http://www") + ".google-analytics.com/ga.js";
var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(ga, s);
})();

You can see that the function is in parentheses.

Why do you think so?

Answer 1

This is an anonymous function that is defined and called immediately. It cannot be called from without because it has no name. All variables inside will be bound to an anonymous function. This can be used to perform some processing in the global area without adding new members to it.

Answer 2

-. , .