I was wondering if it’s possible to achieve that in CSS 2/3 (or if not possible, in JS).
In fact my wish is instead of having this as an image, is to set the percent of filled color with a class (or in js if it’s not possible)

Any tutorial/help is appreciated.
Thanks.
You can’t achieve this result with css. You have to use a canvas element and a javascript framework like http://paperjs.org/