Can anyone assist with validating an email form field using Bootstrap 4 without the need for any additional libraries? I believe it might require a simple JavaScript function at the end of the document to check if the fields match. Any guidance on this matter would be greatly appreciated. It's surprising that this feature isn't already available or documented on the official Bootstrap website, considering it seems like a common requirement.
<!DOCTYPE html>
<html>
<head>
<title>Email Validation with Bootstrap 4</title>
<?php
echo '<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">';
?>
</head>
<body>
<form class="needs-validation" novalidate>
<div class="form-row">
<div class="col-md-4 mb-3">
<label for="validationCustom01">Email</label>
<input type="email" class="form-control" id="email" placeholder="Email" required>
<div class="valid-feedback">
Looks good!
</div>
</div>
<div class="col-md-4 mb-3">
<label for="validationCustom02">Confirm Email</label>
<input type="email" class="form-control" id="confirm_email" placeholder="Confirm Email" required>
<div class="valid-feedback">
Emails should match
</div>
</div>
</div>
<div class="form-group">
<div class="form-check">
<input class="form-check-input" type="checkbox" value="" id="invalidCheck" required>
<label class="form-check-label" for="invalidCheck">
Agree to terms and conditions
</label>
<div class="invalid-feedback">
You must agree before submitting.
</div>
</div>
</div>
<button class="btn btn-primary" type="submit">Submit form</button>
</form>
<script>
// 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');
// check match
// 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);
})();
</script>
</body>
</html>