<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript">
/**
*
*/
var x;
x = window.prompt("数字の入力","","");
x = x * x * x;
document.write(x + '<br/>');


</script>
<body>

</body>
</html>