title: Input type=file onchange event won't fire when calling a user-defined function
body: <p>I can't seem to make onchange fire for an input type of file. If I directly call an alert (like onchange="alert('a')"), it fires but if I call a user-defined function with only an alert inside, it doesn't. see below:</p>
  
  <p>the html:</p>
  
  <pre><code>&lt;input type='file' value='C:\fakepath' onchange="previewFile()"/&gt;
  </code></pre>
  
  <p>the script:</p>
  
  <pre><code>function previewFile() {
      alert("a");
  }
  </code></pre>
  
  <p><a href="http://jsfiddle.net/vDQxj/276/" rel="nofollow">http://jsfiddle.net/vDQxj/276/</a></p>