var brightnessPicker = new iro.ColorPicker('#brightness', {
 color: {
 h: 0,
 s: 0,
 v: 50 // initial value
 },
 layout: [
 { 
 component: iro.ui.Slider,
 options: {
 // can also be 'saturation', 'value', 'red', 'green', 'blue', 'alpha' or 'kelvin'
 sliderType: 'value'
 }
 },
 ]
});