development of interactive web demo for software

I have a software developed in excel that uses VBA & Macros. I want to have a interactive demo version of the software in my website. I understand that it may be very difficult (or not possible) to replicate macro based excel functions in web based demo. That would mean that we will have to restrict entry of data to predefined values and/or restrict number of entries & then write a logic for simulating the behaviour of software for those predefined/restricted entries/ So, the requirements are:- a) To have a web interface identical to the software. b) Allow user to enter some values (that may have to be predefined - if required) c) The output would mirror actual output that we get from software The software is construction works related & involves estimation and analysis of rates. I would be giving demo version of software & explain what features are to demonstrated in subsequent discussions.