As I said this is all very simple, the one thing that makes it a little bit more interesting is the save button. You can do some computations/calculations and s

As I said this is all very simple, the one thing that makes it a little bit more interesting is the save button. You can do some computations/calculations and save the results (by downloading) into the same file or a new file. I have even modified the javascript code of the page itself and saved it away (not really directly supported).