{
  "name": "darker",
  "type": "function",
  "description": "Returns a darker (or lighter) color string",
  "arguments": [
               {"arg":"color", "description":"a color string"},
	{"arg":"factor", "description":"a integer number corresponding to the darkening factor:<ul><li>if the factor is greater than 100, this functions returns a darker color (for e.g., setting factor to 300 returns a color that has one-third the brightness);</li><li>if the factor is less than 100, the return color is lighter, but using the lighter() function for this purpose is recommended;</li><li>if the factor is 0 or negative, the return value is unspecified.</li></ul>"}
	          ],
  "examples": [ { "expression":"darker('200,10,30',300)", "returns":"'66,3,10,255'"}]
}