ch4_example2.html

<!DOCTYPE html>
<html lang="en">
<head>
	<title>Chapter 4, Example 2</title>
</head>
<body>

	<script>
		function toCentigrade(degFahren) {
			var degCent = 5 / 9 * (degFahren - 32);

			document.write(degFahren + " Fahrenheit is " + 
				degCent + " Celsius.<br />");
		}
	
		function toFahrenheit(degCent) {
			var degFahren = 9 / 5 * degCent + 32;

			document.write(degCent + " Celsius is " + 
				degFahren + " Fahrenheit.<br />");
		}

		function convert(converter, temperature) {
			converter(temperature);
		}
	
		convert(toFahrenheit, 23);
		convert(toCentigrade, 75);

	</script>
</body>
</html>