title: File element cant trigger after get it from ajax
body: <p>I have a form upload file from computer.
  My step to upload</p>
  
  <p>1, Click to button</p>
  
  <p>2, After click will run ajax to load the field from server.</p>
  
  <p>3, After loaded that field, I append it to own form. And trigger click it hope a window upload will show. But it does not work. I using jquery 2.1.0</p>
  
  <pre><code>$('.form-file').click();
  </code></pre>
  
  <p>It already and show by console.log</p>