title: Angular $event undefined in Firefox
body: <p>As said in the <a href="http://docs.angularjs.org/api/ng.directive%3angMouseenter" rel="nofollow">angular api docs</a>, ng-mouseenter makes event object available as <code>$event</code>.</p>
  
  <p>HTML:</p>
  
  <pre><code>&lt;div ng-mouseenter="enter('test', $event)"&gt;Enter mouse over here&lt;/div&gt;
  </code></pre>
  
  <p>JS:</p>
  
  <pre><code>$scope.enter = function(data, $event) {
      console.log($event.x);
  };
  </code></pre>
  
  <p><a href="http://jsfiddle.net/HB7LU/445/" rel="nofollow">Use this fiddle</a> and notice that...</p>
  
  <ul>
  <li><p>in chrome the log gives: <code>77</code> (or another number)</p></li>
  <li><p>And firefox gives the log: <code>undefined</code>.</p></li>
  </ul>
  
  <p>Am I using <code>$event</code> the wrong way or does <code>$event</code> not work in Firefox?</p>