title: What does !1 and !0 mean in Javascript?
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/8255653/return-1-in-javascript">return !1 in javascript</a>  </p>
  </blockquote>
  
  
  
  <p>In a JavaScript file I had to read today, there was a line where a variable was declared like a factorial, like this :</p>
  
  <pre><code>var myVariable = !1;
  </code></pre>
  
  <p>and then something similar was used as parameter in a function like this :</p>
  
  <pre><code>return variable.myFunction(!0);
  </code></pre>
  
  <p>Can anyone explain me what the exclamation mark means in this context and eventually, why this is generally used for (benefits) ?</p>
  
  <p>Thank you in advance !</p>