SOURCE

function randomRgb() {
    let r = Math.floor(Math.random() * 256)
    let g = Math.floor(Math.random() * 256)
    let b = Math.floor(Math.random() * 256)

    let rgb = 'rgb(' + r + ',' + g + ',' + b + ')'

    return rgb
}
console.log(randomRgb())

function randomHex() {
    var hex =  parseInt(Math.random() * 0xFFFFFF).toString(16)
    return '#' + hex

}
console.log(randomHex())