Excel Application on the Internet

I don't know if this is a silly question but if anyone could offer some help or point me in the right direction, that would be great. I am currently working on a project where I am creating an interface connecting a bunch of different modules (applications). These modules are for the most part excel based. The company I am working for wants me to create an interface that will link all these modules together in a sequential order. They want the system created to be able to work on the internet as well as be a stand alone application. The users of this system need to be able to manipulate the spreadsheets with data they input. The spreadsheets also need to be able to perform calculations. This data then needs to be saved in a database so that if the user does not want to go through all 19 modules in one day they can come back to it. Ok after all that, my question is, can you put excel spreadsheets on the internet in this fashion. I have seen before where you can download a spreadsheet and work with it, but I have never really seen a spreadsheet that you manipulate on the web (enter data and calculations are performed) and then click a next button to go to the next spreadsheet, and that spreadsheet will pick up any data from the first spreadsheet that may be relevant. If anyone can let me know if this is possible and what you think might be a good development environment to be able to do this, that would be great. Sorry for writing so much.

Thank you,

Aryana