PalGen (PALette GENerator) is a palette generator for things that don't generate colors using plain RGB (for example, old video game consoles). Right now, PalGen is focused on the NTSC version of the NES, but in the future it may be extended to support other things.
What makes PalGen special is that you can specify your own red, green, blue, and white points, so if you want to simulate specific phosphors being used for the different colors (and you know the CIExy values for them), you can do so.
It's HTML5, just download the files and open index.html in your favorite browser. If your intention is to publically host this online, I would appreciate if you would please leave the link to the GitHub project intact.
Copyright (C) DragWx
Licensed under the MIT License, for license body, see the palgen.js file.