HTML Javascript & Asp.net - Security

Hi All,

Application Structure info:

Presentation Layer - HTML & Javascripts only (It contains all the controls and communicate to processing layer by using jquery Ajax json service.)

Processing Layer - Asp.net (It contains common web service/method to process the presentation layer all request (authendication, check users in database and data manipulations from db)). Actually it's an intermediate for database and client UI.

My BIG question is,

What are the methods to secure this structure? and how to solve the below security issues in this structure? 

1. Login page Authentication for all the HTML pages
2. Need to check referrer for all the HTML pages
3. JSON Hijacking  
4. Cross Site Request Forgery or Cross Site Scripting (XSS)
5. JavaScript + CSS files security
6. Remote code execution
7. SQL injection
8. Format string vulnerabilities
9. URLs Visibility

Please help me. Thanks in advance.

Thanks & Regards,

Sathiskumar.P