How to directly get context of WebGL2 from canvas when building with "-sOFFSCREENCANVAS_SUPPORT=1 -sOFFSCREEN_FRAMEBUFFER=1" flags?

[xrui94]

The “-sOFFSCREENCANVAS_SUPPORT=1” and “-sOFFSCREEN_FRAMEBUFFER=1” flags were enabled during compilation, but in some cases, I want to directly get context of webgl2 and webgpu from canvas，not OffscreenCanvas. However, an error occured:

It seems that I should use "canvas.canvas.getContext"？？？My EMSDK version is 3.1.57