Prevent Double Form Submit

no-double-submit.js

$('form').on('submit', function(evt) {
  $('a, button:not([type]), [type="submit"]', this)
    .prop('disabled', true);
  $('a').addClass('is-disabled');  
});

/*  
    The `is-disabled` class is added for the rare case that a link might
    be set up to submit a form, since some browsers won't disable a link.
    
      a.is-disabled {
        pointer-events: none;
        cursor: default;
        color: #999;
      }
*/