Where do you do your validation? model, controller or view

Question

Where do you put user input validation in a web form application?

1. View: JavaScript client side
2. Controller: Server side language (C#...)
3. Model

Answer 1

I only do it in the View and Controller, the database enforces some of that by your data types and whatnot, but I'd rather it not get that far without me catching an error.

You pretty much answered your own question though, the important thing to know is that you can never trust the view, although that's the easiest route to give feedback to the user, so you need to sanitize on at least one more level.