Bootstrap 4 client validation before ajax submit

Question

I have a form (see it below). We follow bootstrap 4 on a project therefore I prefer to re-use as much as possible and do not write my own code where it is not needed.

When user press Submit button I do AJAX post request and as a response I get JSON object with some information. Based on that response I have to do some logic.

<form name="signin" class="js-form-submit needs-validation" action="/signin">
  <div class="form-group">
    <label for="username">User Name</label>
    <input class="form-control" id="username" name="username" autofocus>
  </div>
  <div class="form-group">
    <label for="password">Password</label>
    <input type="password" class="form-control" id="password" name="password" >
  </div>
  <button type="submit" class="btn btn-primary mb-2">Submit/button>
</form>

Now I want to make client-side validation (and I prefer to use bootstrap if possible). They have an example but it works with normal submit but not with AJAX and I'm curious how can I perform bootstrap 4 client-side validation before my AJAX call?

// Example starter JavaScript for disabling form submissions if there are invalid fields
(function() {
  'use strict';
  window.addEventListener('load', function() {
    // Fetch all the forms we want to apply custom Bootstrap validation styles to
    var forms = document.getElementsByClassName('needs-validation');
    // Loop over them and prevent submission
    var validation = Array.prototype.filter.call(forms, function(form) {
      form.addEventListener('submit', function(event) {
        if (form.checkValidity() === false) {
          event.preventDefault();
          event.stopPropagation();
        }
        form.classList.add('was-validated');
      }, false);
    });
  }, false);
})();

https://getbootstrap.com/docs/4.0/components/forms/#custom-styles

Could somebody point me on a direction or maybe give a snippet of code.

Thanks.

Answer 1

I found a solution using JQuery. Try this code,

$('your-form-id').submit(function (event) {
    event.preventDefault();
    if ($('your-form-id')[0].checkValidity() === false) {
        event.stopPropagation();
    } else {
        //do your ajax submition here
    }
    $('your-form-id').addClass('was-validated');
});

Answer 2

Add your ajax request to the else condition statement, this will do it.

// Example starter JavaScript for disabling form submissions if there are invalid fields
    (function() {
      'use strict';
      window.addEventListener('load', function() {
        // Fetch all the forms we want to apply custom Bootstrap validation styles to
        var forms = document.getElementsByClassName('needs-validation');
        // Loop over them and prevent submission
        var validation = Array.prototype.filter.call(forms, function(form) {
          form.addEventListener('submit', function(event) {
            if (form.checkValidity() === false) {
              event.preventDefault();
              event.stopPropagation();
            }else {
               //do your ajax submition here
            }
            form.classList.add('was-validated');
          }, false);
        });
      }, false);
    })();