代码示例:(标识:eg_js_function_variable)
<!DOCTYPE html>
<html>
<body>

<h2>JavaScript 函数</h2>

<p id="demo"></p>

<script>
document.getElementById("demo").innerHTML =
"温度是:" + toCelsius(86) + " 摄氏度。";

function toCelsius(fahrenheit) {
    return (5/9) * (fahrenheit-32);
} 
</script>

</body>
</html>
运行结果: