exercicio 02 MDN method para string

<!DOCTYPE html>
<html lang="pt-br">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="output">
        <ul>

        </ul>
    </div>
    <script>
        var list = document.querySelector('.output ul');
        list.innerHTML = '';
        var cities = ['london','ManCHESter','BiRmiNGHAM','liVERpool'];
        for(var i =0;i<cities.length;i++){
            input = cities[i];
            var lower = input.toLowerCase();
            var firstItem = lower.slice(0,1);
            var captalized = lower.replace(firstItem,firstItem.toUpperCase());
            var result = captalized;
            var listItem = document.createElement('li')
            listItem.textContent = result;
            list.appendChild(listItem);

        }
    </script>
</body>
</html>