javascript - Prevent double submission of forms in jQuery

Question

I have a form that takes a little while for the server to process. I need to ensure that the user waits and does not attempt to resubmit the form by clicking the button again. I tried using the following jQuery code:

<script type="text/javascript">
$(document).ready(function() {
    $("form#my_form").submit(function() {
        $('input').attr('disabled', 'disabled');
        $('a').attr('disabled', 'disabled');
        return true;
    });
});
</script>

When I try this in Firefox everything gets disabled but the form is not submitted with any of the POST data it is supposed to include. I can't use jQuery to submit the form because I need the button to be submitted with the form as there are multiple submit buttons and I determine which was used by which one's value is included in the POST. I need the form to be submitted as it usually is and I need to disable everything right after that happens.

Thanks!

Answer 1

Update in 2018: I just got some points for this old answer, and just wanted to add that the best solution would be to make the operation idempotent so that duplicate submissions are harmless.

Eg, if the form creates an order, put a unique ID in the form. The first time the server sees an order creation request with that id, it should create it and respond "success". Subsequent submissions should also respond "success" (in case the client didn't get the first response) but shouldn't change anything.

Duplicates should be detected via a uniqueness check in the database to prevent race conditions.

---

I think that your problem is this line:

$('input').attr('disabled','disabled');

You're disabling ALL the inputs, including, I'd guess, the ones whose data the form is supposed to submit.

To disable just the submit button(s), you could do this:

$('button[type=submit], input[type=submit]').prop('disabled',true);

However, I don't think IE will submit the form if even those buttons are disabled. I'd suggest a different approach.

A jQuery plugin to solve it

We just solved this problem with the following code. The trick here is using jQuery's data() to mark the form as already submitted or not. That way, we don't have to mess with the submit buttons, which freaks IE out.

// jQuery plugin to prevent double submission of forms
jQuery.fn.preventDoubleSubmission = function() {
  $(this).on('submit',function(e){
    var $form = $(this);

    if ($form.data('submitted') === true) {
      // Previously submitted - don't submit again
      e.preventDefault();
    } else {
      // Mark it so that the next submit can be ignored
      $form.data('submitted', true);
    }
  });

  // Keep chainability
  return this;
};

Use it like this:

$('form').preventDoubleSubmission();

If there are AJAX forms that should be allowed to submit multiple times per page load, you can give them a class indicating that, then exclude them from your selector like this:

$('form:not(.js-allow-double-submission)').preventDoubleSubmission();