I use to make some js for that (Css filters, brightness, contrast etc): Here is a demo on this current page: https://media.giphy.com/media/8lZ5Cyp6rRvrLoXMc1/gi

I use to make some js for that (Css filters, brightness, contrast etc): Here is a demo on this current page: https://media.giphy.com/media/8lZ5Cyp6rRvrLoXMc1/giphy.gif https://media.giphy.com/media/8lZ5Cyp6rRvrLoXMc1/giphy.gif And the project sources with explanations: https://github.com/webdev23/ponyFilters https://github.com/webdev23/ponyFilters HN disallow script embedding, but it still can be injected via console, then by using greasmonkey, settings are kept for next displays.