What's two ";" mean in javascript

Question

When i read javascript file it has tow ";" sometimes,like:

(function($, undefined) {


;;

var defaults = {

    ..........

what that meaning?

It doesn't mean anything special. It's just an empty statement. — Barmar, Dec 10 '13 at 02:44
Not actually an answer (because it's already been answered) but sometimes you'll see ;(function($, undefined) { ... and that is done on purpose to close other previously loaded files (possibly) bad javascript before yours. — Lenny, Dec 10 '13 at 02:47
Sometimes it means breaking it down. See http://stackoverflow.com/questions/6955767/what-does-it-do-jquery-ui-function. — flypen, Dec 10 '13 at 02:48

score 6 · Accepted Answer · answered Dec 10 '13 at 02:44

6

That's just a null statement (known as an "empty statement" by the ECMAScript standard). This works as well:

;;;;;;;;;;;;;;;;;;;;;;;;;;alert('lots of semicolons');;;;;;;;;;;;;;;;;;;

It doesn't mean anything.

answered Dec 10 '13 at 02:44

tckmn

Not that it matters, but ECMAScript calls it an "empty statement". http://es5.github.io/#x12.3 – Blue Skies Dec 10 '13 at 02:45

score 1 · Answer 2 · answered Dec 10 '13 at 02:44

1

It doesn't mean anything special. The second semicolon is just an empty statement and you could safely remove it if you wanted.

answered Dec 10 '13 at 02:44

hugomg

2

Isn't the first semicolon an empty statement as well? – Felix Kling Dec 10 '13 at 02:46
@FelixKling: In this example, yes. However, if the preceding lines were different that might not have been the case. – hugomg Dec 10 '13 at 02:49

score 1 · Answer 3 · answered Dec 10 '13 at 02:45

1

It is probably a typo. It is not necessary.

Here is a link to semicolons in JavaScript that you might find helpful.

answered Dec 10 '13 at 02:45

whoacowboy

3 Answers3