title: Does if you add two not (!) operators in javascript do they negate each other?
body: <p>I have come across some code that includes two consecutive ! operators. Basically the code goes like this:</p>
  <pre><code>var foo = false || !!foo2;
  </code></pre>
  <p>First of all, I know that I can go without the assignment of false... I'm really only confused as to what the !! means in this. Does one ! negate the other? If so, does that just mean that we can remove both occurrences of the ! operator? If not, what does !! do?</p>