title: How can I trigger the upload file with Valums Ajax File-Uploader?
body: <p>When using Valums Ajax file uploader, how can I trigger the upload?</p>
  
  <p>The default behavior is for the upload to begin immediately after the user selects a file. I want to prevent this from happening, and instead trigger the upload when the user clicks a separate "Upload" button after they have selected a file.</p>
  
  <p>I looked through the code and found that the upload begins on the <code>change</code> event attached to the file input. I began by adding <code>return false;</code> to to the <code>onSubmit</code> function, and then attaching a click event to another button that triggered the change event:  </p>
  
  <pre><code>$('#startUpload').on('click', function() {  
      // some conditionals
      $('input[name="file"]').trigger('change');  
  });
  </code></pre>
  
  <p>That doesn't work. It just opens the file menu again.  </p>
  
  <p>How can I prevent the upload from occurring immediately after the user selects the file and instead trigger it when the user clicks another button?</p>