Is there any browser-based animation authoring tool or app out there?

Question

I'm looking for a full feature browser-based animation authoring tool or app with an interface similar to the retired Adobe Flash software.Of course, it should output a movie or HTML canvas file format instead of SWF.

aww_dang · Accepted Answer

https://www.codeandweb.com/free-sprite-sheet-packerI've enjoyed this tool. Edit, I see you've elaborated and this isn't what you're looking for.

Is there any browser-based animation authoring tool or app out there?

I'm looking for a full feature browser-based animation authoring tool or app with an interface similar to the retired Adobe Flash software.
Of course, it should output a movie or HTML canvas file format instead of SWF.

https://www.codeandweb.com/free-sprite-sheet-packer
I've enjoyed this tool. Edit, I see you've elaborated and this isn't what you're looking for.