Is there a way to compare 2 colors in JS, like 'If Color A is darker than #202020'

Question

The background color for one of my pages is set pulled from the background color the users set as their twitter background color. I have a page that has a rounded box with a black border. The border doesnt look good if the background color is dark, so i'd like to remove the border of the background is darker than an arbitrary hex color.

The way I was thinking about doing this was using a regex to pull the 3 RGB values and summing them, and comparing that to my reference color. Is there a better, way to accomplish this?

Answer 1

You could write a function that converts between RGB and HSL or HSV, and use the lightness or brightness value.

Wikipedia has the math for HSV -> RGB conversion, but not the other way.

http://en.wikipedia.org/wiki/HSL_and_HSV#Converting_to_RGB

You could also probably pull some JS from this page.

http://www.csgnetwork.com/csgcolorsel4.html