Angular function declaration understanding

[christopher1225]

Hi all,

I would like to ask a question about javascript( I think it's prototype based) function declarations.
While using third party js module(http://tags.expo9.exponential.com/ta...tv/BTF/tags.js), I am stuck with a question.

Let me list down the function declaration:

expo9_ad = (function() {
var version = "1.20";
var displayAdVersion = "0.3";

function expo9_ad() {
var t = this;
t.host = "a.tribalfusion.com";
...
}

expo9_ad.prototype.showAd = function () {
var t = this;
t.url = "";
...
}
...
...
return expo9_ad;
})();

It seems to me like this :
expo9_ad = (function() {return expo9_ad;})();
But I can't understand how it works.

Any help would be appreciate.
Thank you,
Christopher

[devnull69]

This construct

(function() {
})();

is actually a self-calling anonymous function. It is mostly used to separate the script scope from the global namespace (to prevent cluttering of the global namespace).

In this case a new class is created inside the scope and then returned to the global scope where it is then available with the same name. Actually I don't really see the advantage of using a self-calling anonymous function here.