conditional.html

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<meta http-equiv="X-UA-Compatible" content="ie=edge">
	<title>Document</title>
</head>
<body>
	<script>
		var num1 = prompt('Number 1 :')
		var num2 = prompt('Number 2:')
		var op   = prompt('Operation: ')

		num1 = parseFloat(num1)
		num2 = parseFloat(num2)

		if (op == '+') {
			console.log(num1 + num2)
		} else if (op == '*') {
			console.log(num1 * num2)
		} else if (op == '-') {
			console.log(num1 - num2)
		} else if (op == '/') {
			console.log(num1 / num2)
		} else {
			console.error('Operation not found')
		}

		// if ((50 > 10) || (600 < 10)) {
		// 	console.log('Is true')
		// }
	</script>
</body>
</html>