Untitled

<html>
<head>
    <title>My page</title>
    <script type="text/javascript">

        function ChangeElements() {
            var label = document.getElementById("label");
            var btn = document.getElementById("button");

            label.innerHTML = "You made some changes";
            btn.setAttribute("value", "You clicked me");
        }

    </script>
</head>

<body>
    <p id="label">This is a label</p>
    <input onclick="ChangeElements()" type="button" id="button" value="Click me" />
</body>
</html>