How to use a pre defined offscreencanvas to create GL context?

[lzw1926]

Noticed that this DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR option opt out Module['canvas'] mechanism as default, so seems I can't pass an offscreencanvas to initial Module and use to create GL context. So what's the correct way to do that?

[sbc100]

I think there are some docs here: https://emscripten.org/docs/api_reference/html5.h.html#registration-functions