A Phone screen..

Had a phone screen with a techie firm from the bay area, Here are some of the questions:

1. Explain a 3 tier web application?
2. What is an n-tier web appliaction?
3. Explain the MVC pattern..
4. How do you implement a login functionality with an MVC?
5. How does the browser back button or refresh affect the login functionality?
6. How do you secure the password? (get or post?)
7. Describe a situation where get would be better.
8. Explain the principles of Ajax?..
9. Which browser object is responsible for getting and posting the request in Ajax?
10. Which html tag would you use to create a list of numbers on a html page?
11. What is the difference between an HTML div and an HTML span tag.
12. Implement a function that returns 1 when 2 is passed and vice versa.
13. Implement the above with divison or bit shift
14. Which one would be most efficient in terms of memory and performance for Q.12: If-else or Array or HashMap or 13?
15. What is SQL injection? How to protect the final query from becoming ill formed due to use of keywords in the form input?