Why do you need to invoke an anonymous function on the same line?

Question

I was reading some posts about closures and saw this everywhere, but there is no clear explanation how it works - everytime I was just told to use it...:

//          


        

Answer 1

(function (msg){alert(msg)})
('SO');

This is a common method of using an anonymous function as a closure which many JavaScript frameworks use.

This function called is automatically when the code is compiled.

If placing ; at the first line, the compiler treated it as two different lines. So you can't get the same results as above.

This can also be written as:

(function (msg){alert(msg)}('SO'));

For more details, look into JavaScript/Anonymous Functions.