index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>main.js
'use strict';
//console.log(50 + '20');
const score = Number(prompt('Score?'));
if (score >= 90) {
console.log('A!');
} else if (score >= 70) {
console.log('B');
} else {
console.log('C!');
}
