Coding a basic buy to let mortgage calculator

This should be pretty straightforward. I started coding this and the raw/basic functions kinda work but I don't have time to flesh this out fully so it's: 1. Secure - I've done nothing to secure the forms etc. 2. The HTML/CSS looks nice 3. Fully functional (I've tried the basic calculations only - all the outputs/displays and fancy stuff needs doing). Feel free to bid on starting from scratch as my code will just give you an idea of which calculations I need rather than be a good base for the project tbh. These guys have a more complex version of what I'm looking for. If you imagine this but with about 2/3 as many features that's about what I'm shooting for: [login to view URL]