title: RemoveEventListener does not work on named function
body: <p>I am twisting my mind and fingers finding why <code>removeEventListener</code>won't work. It should be a one time event, so I included the <code>removeEventListener</code> in the callback function, but the event fires every time.</p>
  <pre><code>var group = ...//some div's ID
  var img_button = document.createElement(&quot;SPAN&quot;);
      img_button.setAttribute(&quot;id&quot;,&quot;imgbutton_&quot;+group);
  if (figures.addEventListener){
      figures.addEventListener(
      'click', function(e){if (!e) e = window.event;e.stopPropagation();}, false);
      img_button.addEventListener(
      'mouseover', loadImg(group), false);
      }else{...};
  </code></pre>
  <p>And the callback <code>loadImg</code>:</p>
  <pre><code>function loadImg(nodeId){//loading images when needed
      return function(e){
          if (!e) e = window.event;
  [...]
      //remove eventlistener when executed once
          var sp = (e.target ? e.target : e.srcElement);
          
          if (sp.removeEventListener){
              sp.removeEventListener(
              'mouseover', loadImg);
          } else {...};
  };
  </code></pre>
  <p>The anonymous function can stay but the <code>loadImg</code> I only need once. What did I forget?</p>