<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="Cache-Control" content="no-cache">
<title>Example</title>
<style>
input {
width: 3em;
}
</style>
<script defer src="example.js"></script>
</head>
<body>
<noscript>Enable JavaScript to see web page content.</noscript>
<p><input id="fahrenheit">° Fahrenheit is <output id="celsius"></output>° Celsius</p>
</body>
</html>
// This program converts a Fahrenheit temperature to Celsius.
//
// References:
// https://www.mathsisfun.com/temperature-conversion.html
// https://en.wikibooks.org/wiki/JavaScript
"use strict";
const TEMPERATURE_DIFFERENCE = 32;
const TEMPERATURE_RATIO = 5 / 9;
window.addEventListener("load", function () {
document.getElementById("fahrenheit").addEventListener("input", fahrenheitInput);
});
function fahrenheitInput() {
let fahrenheit = getFahrenheit();
let celsius = fahrenheitToCelsius(fahrenheit);
displayResults(fahrenheit, celsius);
}
function getFahrenheit() {
let fahrenheit = document.getElementById("fahrenheit").value;
fahrenheit = Number(fahrenheit);
return fahrenheit;
}
function fahrenheitToCelsius(fahrenheit) {
let celsius = (fahrenheit - TEMPERATURE_DIFFERENCE) * TEMPERATURE_RATIO;
return celsius;
}
function displayResults(fahrenheit, celsius) {
celsius = celsius.toFixed(1);
document.getElementById("celsius").innerText = celsius;
}
