title: What does 0x0F mean? And what does this code mean?
body: <p>I have this code. Please make me understand what does this code actually mean</p>
  
  <pre><code>  for(var i = 0; i &lt; input.length; i++)
    {
      x = input.charCodeAt(i);
      output += hex_tab.charAt((x &gt;&gt;&gt; 4) &amp; 0x0F)
             +  hex_tab.charAt( x        &amp; 0x0F);
    }
  </code></pre>
  
  <p>What is 0x0F? And, >>> Mean?</p>