HTML5 Volume Control
Form Slider via input type="range" and output Element via demosthen.es demosthenes.info/blog/757/Playing-With-The-HTML5-range-Slider-Input
HTML
<label for=fader>Volume</label>
<input type=range min=0 max=100 value=50 id=fader step=1 onchange="outputUpdate(value)">
<output for=fader id=volume>50</output>
JavaScript
function outputUpdate(vol) {
document.querySelector('#volume').value = vol;
}