datepicker for date of birth in javascript

<div class="container">
        <h2>Date of Birth</h2>
        <form id="dobForm">
            <div class="form-group">
                <label for="dob">Select your date of birth</label>
                <input type="date" id="dob" name="dob" required>
                <div class="error" id="error"></div>
            </div>
            <button type="submit">Calculate Age</button>
        </form>
        <div class="result" id="result">
            <div class="result-text" id="resultText"></div>
        </div>
    </div>

    * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            background: linear-gradient(135deg, #00c6ff 0%, #0072ff 100%);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 20px;
        }

        .container {
            background: white;
            border-radius: 12px;
            padding: 40px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            max-width: 400px;
            width: 100%;
        }

        h2 {
            color: #333;
            margin-bottom: 24px;
            font-size: 24px;
            font-weight: 600;
        }

        .form-group {
            margin-bottom: 20px;
        }

        label {
            display: block;
            margin-bottom: 8px;
            color: #555;
            font-size: 14px;
            font-weight: 500;
        }

        input[type="date"] {
            width: 100%;
            padding: 12px 16px;
            border: 2px solid #e0e0e0;
            border-radius: 8px;
            font-size: 16px;
            color: #333;
            transition: all 0.3s ease;
            background: white;
        }

        input[type="date"]:focus {
            outline: none;
            border-color: #00c6ff;
            box-shadow: 0 0 0 3px rgba(0, 198, 255, 0.1);
        }

        input[type="date"]:hover {
            border-color: #00c6ff;
        }

        button {
            width: 100%;
            padding: 14px;
            background: linear-gradient(135deg, #00c6ff 0%, #0072ff 100%);
            color: white;
            border: none;
            border-radius: 8px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s ease, box-shadow 0.2s ease;
        }

        button:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(0, 198, 255, 0.4);
        }

        button:active {
            transform: translateY(0);
        }

        .result {
            margin-top: 20px;
            padding: 16px;
            background: #f5f7fa;
            border-radius: 8px;
            border-left: 4px solid #00c6ff;
            display: none;
        }

        .result.show {
            display: block;
            animation: slideIn 0.3s ease;
        }

        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(-10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .result-text {
            color: #333;
            font-size: 14px;
            line-height: 1.6;
        }

        .result-text strong {
            color: #0072ff;
        }

        .error {
            color: #e74c3c;
            font-size: 13px;
            margin-top: 8px;
            display: none;
        }

        .error.show {
            display: block;
        }

   const form = document.getElementById('dobForm');
        const dobInput = document.getElementById('dob');
        const result = document.getElementById('result');
        const resultText = document.getElementById('resultText');
        const error = document.getElementById('error');

        const today = new Date().toISOString().split('T')[0];
        dobInput.setAttribute('max', today);

        const minDate = new Date();
        minDate.setFullYear(minDate.getFullYear() - 120);
        dobInput.setAttribute('min', minDate.toISOString().split('T')[0]);

        form.addEventListener('submit', (e) => {
            e.preventDefault();
            error.classList.remove('show');
            
            const dob = new Date(dobInput.value);
            const now = new Date();

            if (!dobInput.value) {
                showError('Please select a date of birth');
                return;
            }

            if (dob > now) {
                showError('Date of birth cannot be in the future');
                return;
            }

            const age = calculateAge(dob, now);
            
            resultText.innerHTML = `
                <strong>Date of Birth:</strong> ${formatDate(dob)}<br>
                <strong>Age:</strong> ${age.years} years, ${age.months} months, and ${age.days} days
            `;
            result.classList.add('show');
        });

        function calculateAge(dob, now) {
            let years = now.getFullYear() - dob.getFullYear();
            let months = now.getMonth() - dob.getMonth();
            let days = now.getDate() - dob.getDate();

            if (days < 0) {
                months--;
                const lastMonth = new Date(now.getFullYear(), now.getMonth(), 0);
                days += lastMonth.getDate();
            }

            if (months < 0) {
                years--;
                months += 12;
            }

            return { years, months, days };
        }

        function formatDate(date) {
            const options = { year: 'numeric', month: 'long', day: 'numeric' };
            return date.toLocaleDateString('en-US', options);
        }

        function showError(message) {
            error.textContent = message;
            error.classList.add('show');
            result.classList.remove('show');
        }