function colourRandom() {
  var num = Math.floor(Math.random() * 0x1000000);
  return '#' + ('00000' + num.toString(16)).substr(-6);
}

function colourRgb(r, g, b) {
  r = Math.max(Math.min(Number(r), 100), 0) * 2.55;
  g = Math.max(Math.min(Number(g), 100), 0) * 2.55;
  b = Math.max(Math.min(Number(b), 100), 0) * 2.55;
  r = ('0' + (Math.round(r) || 0).toString(16)).slice(-2);
  g = ('0' + (Math.round(g) || 0).toString(16)).slice(-2);
  b = ('0' + (Math.round(b) || 0).toString(16)).slice(-2);
  return '#' + r + g + b;
}

function colourBlend(c1, c2, ratio) {
  ratio = Math.max(Math.min(Number(ratio), 1), 0);
  var r1 = parseInt(c1.substring(1, 3), 16);
  var g1 = parseInt(c1.substring(3, 5), 16);
  var b1 = parseInt(c1.substring(5, 7), 16);
  var r2 = parseInt(c2.substring(1, 3), 16);
  var g2 = parseInt(c2.substring(3, 5), 16);
  var b2 = parseInt(c2.substring(5, 7), 16);
  var r = Math.round(r1 * (1 - ratio) + r2 * ratio);
  var g = Math.round(g1 * (1 - ratio) + g2 * ratio);
  var b = Math.round(b1 * (1 - ratio) + b2 * ratio);
  r = ('0' + (r || 0).toString(16)).slice(-2);
  g = ('0' + (g || 0).toString(16)).slice(-2);
  b = ('0' + (b || 0).toString(16)).slice(-2);
  return '#' + r + g + b;
}


'#ff0000';

'#3333ff';

colourRandom();

colourRgb(100, 50, 0);

colourRgb(0, 1, 20);

colourBlend('#ff0000', '#3333ff', 0.5);

colourBlend('#000000', '#ffffff', 0.3);
