This is what I want to do and I'm wondering if its posible at all.

Ok, I will create a template worksheet in excell doing diferent
functions and what not. will put this worksheet in a website. Now,
What I want to do is make an applet in which a client can have acces
to that work sheet. The client will then be able to edit the
worksheet just like if MS excel was in their machine. How can I do
something like this?