document.on("change", "form", function(ev, form){ const v = form.value; document.style.variables { "red-channel": v.red + "%", "green-channel": v.green + "%", "blue-channel": v.blue + "%", "alpha-channel": v.alpha + "%", }; document.$("#rgba1").value = printf("rgba(%d%%,%d%%,%d%%,%d%%)", v.red, v.green, v.blue, v.alpha); document.$("#rgba2").value = printf("#%02x%02x%02x%02x", v.red * 2.55 + 0.5, v.green * 2.55 + 0.5, v.blue * 2.55 + 0.5, v.alpha * 2.55 + 0.5); });