Some info on the different labels: The opposites are just that, opposites of the red, green, and blue values. Half opposites are the red, green, and blue values with a half of the color scale added to them. Red, green, and blue shifts are shifts toward those colors. Check out #000000 to get an idea of how this works.
This experiment should work in all modern browsers (Chrome, Safari, Firefox, Opera, IE 9+).
Color picker is FlexiColorPicker. Super easy to use, highly recommend.