01.ListOfItems

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Homework</title>
</head>
<body>
    <h1>List of items</h1>
    <ul id="items">
        <li>first</li>
        <li>second</li>
    </ul>
    <input type="text" id="newItemText" />
    <input type="button" value="Add" onclick="addItem()" />

    <script>
        function addItem() {
            let newValue = document.getElementById('newItemText');
            let collection = document.getElementById('items');
            let newLi = document.createElement('li');
            newLi.textContent = newValue.value;
            collection.appendChild(newLi);
            newValue.value = '';
        }
    </script>
</body>
</html>