gistfile1.js

function rgbToHex(r, g, b) {
  return toHex(r) + toHex(g) + toHex(b);
}

function toHex(n) {
  if (n == null) { return '00'; }
  n = parseInt(n);
  if (n == 0 || isNaN(n)) { return '00'; }
  n = Math.max(0, n); n = Math.min(n, 255); n = Math.round(n);
  chars = '0123456789ABCDEF';
  return chars.charAt((n - n % 16) / 16) + chars.charAt(n % 16);
}