code: function(rgbaStr) {
              // lazy create the regex
              if(!this.rgbaRegex) {
                  this.rgbaRegex = /^rgba\(\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,\s*(\d{1,3})\s*,[\s\d.]+\)\s*$/;
              }
              var colorComponents = this.rgbaRegex.exec(rgbaStr);
              if(!colorComponents) {
                  return rgbaStr;
              }
              return ("rgb(" + colorComponents[1] + ", " + colorComponents[2] + ", " + colorComponents[3] + ")");
          }
docs: given a color string in rgba format, returns the equivalent color in rgb format if the color string is not in valid rgba format, returns the color string un-modified