title: JavaScript addEventListener
body: <p>When I use <code>addEventListener</code> only once, like in the example file input, should I remove the listener as well with <code>removeEventListener</code>? Or, if I know that I will not use any of that code anymore, then <em>garbage collector</em> will collect all the objects anyway?</p>
  
  <p>Also, if I remove the event listener manually, will it speed up the garbage collector as it makes its job easier?</p>
  
  <pre><code>  var file    = document.querySelector('input[type=file]').files[0];
    var reader  = new FileReader();
  
    reader.addEventListener("load", function () {
      preview.src = reader.result;
    }, false);
  
    if (file) {
      reader.readAsDataURL(file);
    }
  </code></pre>