<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>JavaScript Form Validation</title>
    <style>
        .error-message {
            color: red;
            font-size: 0.8em;
            margin-top: 5px;
        }
    </style>
</head>
<body>
    <h2>JavaScript Form Validation Example</h2>

    <form id="myForm">
        <label for="name">Name:</label>
        <input type="text" id="name" name="name" required>
        <span class="error-message" id="nameError"></span>

        <br><br>

        <label for="email">Email:</label>
        <input type="email" id="email" name="email" required>
        <span class="error-message" id="emailError"></span>

        <br><br>

        <label for="age">Age:</label>
        <input type="number" id="age" name="age" min="18" max="99" required>
        <span class="error-message" id="ageError"></span>

        <br><br>

        <label for="password">Password:</label>
        <input type="password" id="password" name="password" required>
        <span class="error-message" id="passwordError"></span>
        <br><br>
        <input type="submit" value="Submit">
    </form>
</body>
</html>

        body {
            font-family: Arial, sans-serif;
            background-color: #f0f0f0;
            padding: 20px;
        }

        h2 {
            color: #333;
            text-align: center;
        }

        form {
            max-width: 400px;
            margin: 0 auto;
            background: #fff;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0,0,0,0.1);
        }

        label {
            font-weight: bold;
        }

        input[type="text"],
        input[type="email"],
        input[type="number"],
        input[type="password"] {
            width: calc(100% - 20px);
            padding: 10px;
            margin: 8px 0;
            border: 1px solid #ccc;
            border-radius: 4px;
        }

        input[type="submit"] {
            background-color: #4CAF50;
            color: white;
            padding: 12px 20px;
            border: none;
            border-radius: 4px;
            cursor: pointer;
            width: 100%;
            margin-top: 10px;
            font-size: 16px;
        }

        input[type="submit"]:hover {
            background-color: #45a049;
        }

        .error-message {
            color: red;
            font-size: 0.8em;
            margin-top: 5px;
        }
        const form = document.getElementById('myForm');

        form.addEventListener('submit', function(event) {
            // Prevent default form submission
            event.preventDefault();

            // Perform validation
            if (validateForm()) {
                // Submit the form
                alert('Form submitted successfully!');
                form.reset(); // Optional: Reset the form after submission
            }
        });

        function validateForm() {
            let isValid = true;

            // Validate name
            const name = document.getElementById('name').value.trim();
            const nameError = document.getElementById('nameError');
            if (name === '') {
                nameError.textContent = 'Name is required';
                isValid = false;
            } else if (name.length < 3 || name.length > 16) {
                nameError.textContent = 'Name is to short ';
                isValid = false;
            } else {
                nameError.textContent = '';
            }

            // Validate email
            const email = document.getElementById('email').value;
            const emailError = document.getElementById('emailError');
            if (!isValidEmail(email)) {
                emailError.textContent = 'Please enter a valid email address';
                isValid = false;
            } else {
                emailError.textContent = '';
            }

            // Validate age
            const age = document.getElementById('age').value;
            const ageError = document.getElementById('ageError');
            if (age < 18 || age > 99) {
                ageError.textContent = 'Age must be between 18 and 99';
                isValid = false;
            } else {
                ageError.textContent = '';
            }

            // Validate password
            const password = document.getElementById('password').value;
            const passwordError = document.getElementById('passwordError');
            if (password.length < 8) {
                passwordError.textContent = 'Password must be at least 8 characters long';
                isValid = false;
            } else {
                passwordError.textContent = '';
            }

            return isValid;
        }

        function isValidEmail(email) {
            const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
            return emailRegex.test(email);
        }

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.