Triple (3) Equal Signs
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/359494/javascript-vs-does-it-matter-which-equal-operator-i-use">JavaScript === vs == : Does it matter which &ldquo;equal&rdquo; operator I use?</a>  </p>
</blockquote>



<p>I asked <a href="http://stackoverflow.com/questions/11112127/prevent-backspace-from-navigating-back-with-jquery-like-googles-homepage">another question</a> here and received a great answer as follows:</p>

<pre><code>$(document).on("keydown", function (e) {
  if (e.which === 8 &amp;&amp; !$(e.target).is("input, textarea") || $(e.target).is('[readonly]')) {
      e.preventDefault();
  }
}); 
</code></pre>

<p>Notice the three equal signs <code>===</code> in the if-statement. I have always thought you only needed two equal signs <code>==</code> for a javascript/jQuery if-statement. Is there any reason for the three?</p>

<p><strong>UPDATE</strong></p>

<p>Sorry for the duplicate question - I searched but didn't find any good questions. I guess I was using the wrong search terms.</p>
