Why is event.target in my code can't run in firefox?
<p>Why is event.target in my code can't run in firefox?   </p>

<pre><code> &lt;script&gt; 
    document.onmousedown = function(){
     var e = window.event;
     var target = e.srcElement || e.target || e.currentTarget;
     if(target.className == 'box'){
     alert("Yeah");
     }
     }
    &lt;/script&gt;



&lt;body&gt;
  &lt;div class="box" style="border:1px dotted #CC3366; width:300px; height:100px;"&gt;Click Me!!&lt;/div&gt;
  &lt;a href="#" class="box"&gt;Link&lt;/a&gt;
 &lt;/body&gt;
</code></pre>

<p>It can run in IE or Chrome but it not in firefox.</p>
