Bootstrap email validation

Question

I'm using Bootstrap to validate email address:

<form id="..." novalidate>
...
<div class="form-group">
    <input type="email" class="form-control" id="..." required/>
        <div class="invalid-feedback">
            Please provide a valid email.
        </div>
</div>
...
</form>

I'm using novalidate property to allow Bootstrap validate email itself. My HTML contains both Bootstrap CSS and JS refs. Everything works fine.

But I have couple of questions:

1. How bootstrap validates email regex? Where can I find code responsible for this (I've tried to look at srcs...)?
2. Can I override regex that is used for validation (would be nice to do this without Bootstrap original code modification)?

Thanks in advance.

Answer 1

Its a late answer, but for those wants to know the answer for second question. Here is the sample code, I tried and was successful. Basically you can add "pattern" attribute to the input field.

(function() {
  'use strict';
  window.addEventListener('load', function() {
    var forms = document.getElementsByClassName('needs-validation');
    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);
})();

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>



<form class="row position-relative flex-column needs-validation" novalidate>
          <input type="email" name="email" placeholder="Your email ID.." class="email white col-7 col-md-4 col-lg-7 ml-3 form-control" id="email" pattern="[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,4}$" required>
          <div class="valid-feedback feedback-pos">
            Looks good!
          </div>
          <div class="invalid-feedback feedback-pos">
            Please input valid email ID
          </div>
          <button type="submit" class="btn btn-danger text-uppercase sbmt-btn col-3 col-md-2 col-lg-4 ml-1" value="validate">Submit</button>
        </form>