Edit in JSFiddle

$(function() {
  $('#my-form').on('change', '[type="text"]', function() {
    $(this).submit();
  });

  $('#my-form').on('submit', function(event) {
    alert('Submitted!');

    event.preventDefault();
  });
});

<form id="my-form" action="#" method="post">
  <input type="text">
</form>