How to judge whether the device supports webGL？
Here you can check if your browser supports WebGL 1 and 2 :
Have a nice day,
Is there any fn or interface？
What is fn ?
What do you mean by interface ?
Fn is for “function” I guess.
Yes, that’s what I supposed as well, but the question is still not very clear.
Is there any method or function can I use to judge whether the device supports webGL in program？
like Detector.js in three.js
By the time you get to the preloader, it is already assumed that WebGL is available. There is no earlier hook within the engine AFAIK.
You would have to write your own wrapper/entry page/portal to the app if that is a concern.