JavaScript Color Picker is a program virtually identical to this one called JS Color Picker. It is a JavaScript library that will generate, through source code, the typical color selectors, as well as obtain the color code that the user selects.
With the functions that the JavaScript Color Picker library is equipped with, you can obtain the values in RGB, HSL and Hexadecimal (much like the Photoshop color picker does). In addition, it is totally free (although its authors ask for a donation if you like its operation).
Having all these functions of JavaScript Color Picker will save you a lot of effort and programming time, because by just referencing them you will be able to generate the selector, obtain the colors, control the possible events, etc.
You can free download JavaScript Color Picker 32, 64 bit and safe install the latest trial or new full version for Windows 10 from the official site.