javascript semantics
<p>I am trying upgrade my javascript programming skills ( or lets say my programming skills period : ) )</p>

<p>so I am trying to understand some semantics :</p>

<p>in the first line what does the "?" mean as well as the minus sign in "-distance"</p>

<p>in the second line what does '+=' or '-=" mean?</p>

<pre><code> el.css(ref, motion == 'pos' ? -distance : distance)

animation[ref] = (mode == 'show' ? (motion == 'pos' ? '+=' : '-=') : (motion == 'pos' ? '-=' : '+=')) + distance;
</code></pre>

<p>thank you</p>
