How to determine white color, or close to it in Javascript?

Question

JavaScript

There is a chat in which the user can specify any color of the nickname.
The background in the chat is white.
The user sets the color through color HTML 5, the output is something #FF00FF.
The prohibition of white color does nothing. Start using light blue, pink or gray.
Can I somehow programmatically define a shade of white that will not be visible in the chat?

Answer 1

Enter a certain threshold of lightness (experimentally select), lighter than which the color will be prohibited. Translate the color in grayscale (0.299*R + 0.587*G + 0.114*B) and compare with the threshold value: if it is lower, skip it, if not, do not allow this color to be set.

Answer 2

Perhaps this question will help.
How to determine if a color is dark?

Answer 3

Convert to HSB and see if the B is too high for the S low.