title: reverse string obfuscation that uses base64
body: <p>I found below javascript code to convert a string to an obfuscated base64 string.</p>
  
  <p>But how to convert it back?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>` 
  
  function strobuscate(a) {
        return (a.split('').map(function(c, i) {
          return String.fromCharCode(c.charCodeAt(0) + i % 80);
        }).join('');
      }
  
  `</code></pre>
  </div>
  </div>
  </p>