Untitled

<!DOCTYPE html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title>Exercicio 4 - Nome Completo</title>
</head>
<body>
    <label for="nome">Nome Completo:</label>
    <input name="nome" id="nome" placeholder="Exibir Nome"/>
    <button onclick="alert(document.getElementById('nome').value);">Exibir Nome</button>

</body>
</html>