viewof rgb = {
const form = html`<form>
<div><input type=range name=r min=0 max=255 step=1 value=127> <i>r</i></div>
<div><input type=range name=g min=0 max=255 step=1 value=127> <i>g</i></div>
<div><input type=range name=b min=0 max=255 step=1 value=127> <i>b</i></div>
</form>`;
form.oninput = () => form.value = [
form.r.valueAsNumber,
form.g.valueAsNumber,
form.b.valueAsNumber
];
form.oninput();
return form;
}