I really like your idea of having a "willitwork" page that dynamically lists the specific deficiencies in the user's browser. So many web applications just silently fail. This is way better. Every web application should have a willitwork page.
I really like your idea of having a "willitwork" page that dynamically lists the specific deficiencies in the user's browser. So many web applications just silently fail. This is way better. Every web application should have a willitwork page.
To detect the availability of the feature, I am chechking if the constructor is available, or if some property of an object is available. I never try to whitelist or blacklist any specific OS or a browser. I have never made any part of the code behave differently for some OS or some browser. But I have reported dozens of bugs to browser developers, most of them were fixed.
Photopea runs quite well on phones and tablets. If your microwave oven passes WillItWork, it will work on it too :)
FYI, Modernizr is a fantastic library for browser feature testing. You can just "add to cart" the tests you want to perform. No hand rolling necessary: https://modernizr.com/