HTML5 Web Application Development By Example Beginner's guide

Time for action – adding a volume control

Going back into the HTML, let's add a range input control to allow the user to change the volume. We will put it right under the sustain label and control we just added:

<label for="volume">Volume: </label>
<input type="range" id="volume" min="1" max="100" value="100" step="1" />

We define a label and a range input with an id attribute of volume. We set the range of the control from 1 to 100 with a step value of 1. We also default the value to 100.

Back in our PianoApp object we add another global variable named volume and set it to 1.0, the maximum volume, by default:

function PianoApp()
{
    var version = "6.3",
    // Code not shown...
    sustain = true,
    volume = 1.0;

Like the sustain checkbox, we need to add a