Potenciação

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        <title> Testando JavaScript </title>

        <style> </style>

        <script type="text/javascript">

            function quadrado(num)
            {
                return(Math.pow(num, 2));
            }

            var num = prompt("Digite um Número: ", 0);

            alert("--- Resultado --- \n\n ["+ num +"]² = " + quadrado(num));

        </script>
    </head>

<body>

</body>

</html>