Convert hex colors to rgba

hex2rgb.js

/**
 * hex2rgb - function for converting hex colors to rgb(a)
 * 
 * Shout out to http://hex2rgba.devoth.com/
 *
 * @hex (String) - The hex value. Can be prefixed with "#" or not. Can be
 *   long format (6 chars) or short format (3 chars)
 * @opacity (number between 0 and 1) - This is an optional float value that
 *   will be used for the opacity
 * 
 * returns (Object) - an object with r, g, and b properties set as numbers
 *   along with a "css" property representing the css rule as a string
 */
function hex2rgb(hex, opacity) {
  hex = (hex + '').trim();

  var rgb = null
    , match = hex.match(/^#?(([0-9a-zA-Z]{3}){1,3})$/);

  if(!match) { return null; }
  
  rgb = {}

  hex = match[1];
  // check if 6 letters are provided
  if (hex.length == 6) {
    rgb.r = parseInt(hex.substring(0, 2), 16);
    rgb.g = parseInt(hex.substring(2, 4), 16);
    rgb.b = parseInt(hex.substring(4, 6), 16);
  }
  else if (hex.length == 3) {
    rgb.r = parseInt(hex.substring(0, 1) + hex.substring(0, 1), 16);
    rgb.g = parseInt(hex.substring(1, 2) + hex.substring(1, 2), 16);
    rgb.b = parseInt(hex.substring(2, 3) + hex.substring(2, 3), 16);
  }

  rgb.css = 'rgb' + (opacity ? 'a' : '') + '(';
  rgb.css += rgb.r + ',' + rgb.g + ',' + rgb.b;
  rgb.css += (opacity ? ',' + opacity : '') + ')';

  return rgb;
}