With web many things are possible.
There is not an easy/direct way to do it using Xojo only.
You may need CSS and maybe JS, or even create WebSDK depending on your needs.
Edit: here is a post with sample code on some CSS animations: Web2.0 External Libraries And Helpers Example Project - Nash - #2 by Brock_Nash
I haven’t played with ‘scrolling animations’, not sure if that link will help.