title: Preventing file upload by submitting a form which has file tag
body: <p>My client has millions of users driver website. I had to implement a custom file upload using AJAX/jQuery.</p>
  <p>The file upload field is just needed to create a clickable and drop-downable file upload mechanism. Everything is working fine except when I submit the form it uploads the file again which has already been uploaded using ajax.</p>
  <p>How can I prevent this uploading?</p>