<!doctype html>
<html lang="en">
<head>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<!-- Bootstrap CSS -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css"
integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
<title>Contact Form</title>
</head>
<body>
<div class="container">
<div class="row">
<div class="col-md-6 mx-auto mt-5">
<h1 class="p-5">👽😅😋👻💩😧😬💀🙌🙀</h1>
<form action="" method="POST">
<div class="form-group">
<label>Name:</label>
<input type="text" class="form-control" id="name" placeholder="Name">
<div class="invalid-feedback">
Name must be between 2 and 20 characters
</div>
</div>
<div class="form-group">
<label>Email:</label>
<input type="text" class="form-control" id="email" placeholder="Email address">
<div class="invalid-feedback">
Enter a valid email address
</div>
</div>
<div class="form-group">
<label>Telephone:</label>
<input type="text" class="form-control" id="phone" placeholder="Phone number">
<div class="invalid-feedback">
Enter a valid number
</div>
</div>
<input type="submit" value="Submit" class="btn btn-info btn-block">
</form>
</div>
</div>
</div>
<!-- Optional JavaScript -->
<!-- jQuery first, then Popper.js, then Bootstrap JS -->
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"
integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo"
crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js"
integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1"
crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js"
integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM"
crossorigin="anonymous"></script>
<script src="index.js"></script>
</body>
</html>
const name = document.getElementById('name');
const email = document.getElementById('email');
const phone = document.getElementById('phone')
name.addEventListener('blur', valName);
email.addEventListener('blur', valEmail);
phone.addEventListener('blur', valPhone);
function valName() {
const re = /^[a-zA-Z]{2,20}$/;
if(!re.test(name.value)) {
name.classList.add('is-invalid');
} else {
name.classList.remove('is-invalid');
}
}
function valEmail() {
const re = /^([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5})$/;
if(!re.test(email.value)) {
email.classList.add('is-invalid');
} else {
email.classList.remove('is-invalid');
}
}
function valPhone() {
const re = /^[0-9\-\+]{9,15}$/;
if(!re.test(phone.value)) {
phone.classList.add('is-invalid');
} else {
phone.classList.remove('is-invalid');
}
}
External CSS
This Pen doesn't use any external CSS resources.