How to create web page with spreadsheet like functionality?

Hello,

I'm looking for a tool that would allow me to create a web page with the
spreadsheet like functionality. Basically, I want to be able to type in a
number in the cell and have all totals being calculated automatically
without having a page refreshed (or a trip to the server). That would be
possible to do with MS Excel web plug-in but I don't want to use plug-ins. I
want users to just access the page and don't worry if they have MS Excel or
MS plug-ins installed.
Is there a solution that would accomplish that? I can be written in any
language like ASP, JSP, DHTML, PYTHON or PHP or a third party tool. I really
don't care. I just wont to create a page with the spreadsheet like
functionality.

Any help is greatly appreciated,
Les