What do ? and : mean in javascript
<p>I am trying to understand the Javascript/jQuery in this  <a href="http://www.queness.com/post/12078/create-jquery-pinterest-pin-it-plugin" rel="nofollow">http://www.queness.com/post/12078/create-jquery-pinterest-pin-it-plugin</a> plugin. The lines 20 and 22 are confusing me, the code is:</p>

<pre><code>pi_media = e.data('media') ? e.data('media') : e[0].src,

pi_desc = e.attr('title') ? e.attr('title') : e.attr('alt'),
</code></pre>

<p>Can anyone help me out with what these lines mean in Javascript</p>
