What is the meaning of the colon (:) and question mark (?) in jquery?

Hi everyone, can the someone tell me what the meaning of the colon ) and the question mark (?) is in the following line of code?

var $next =  $active.next().length ? $active.next()
        : $('#slideshow IMG:first');[CODE]

Code (markup):

[/CODE]

I got the code from this tutorial: http://jonraasch.com/blog/a-simple-jquery-slideshow

Thanks

 

That's an inline if:

If true, do the thing before the question mark, otherwise do the thing after the colon. IOW, if $active.next() has a length (is not 0) $next = $active.next(), else $next = $('#slideshow IMG:first'). It's JS, not jQuery. (Only the $('#slideshow IMG:first') part is jQuery.) The syntax (aside from the jQuery part) is the same in PHP.

 

Thank you very much.

 

Slight edit (what I said is actually pretty stupid):

If true, do the thing after the question mark, otherwise do the thing after the colon. The thing before the question mark is what you're testing.

 

I thought that was what you meant. I vaguely remember seeing this in a tutorial some time ago. Can you point me to one or more tutorials on this?

again Thank You

 

I found the jquery concepts explained in a much precise way here. May be you can fine the answers here.
http://www.hscripts.com/tutorials/jquery/index.php

 

if $active.next().length is true, execute $active.next() else execute $('#slideshow IMG:first')

 

I'd recommend w3schools...