Back-end: Validating Credentials

• Checking for correct HTTP method
• Checking credentials to prevent CSRF & XSS:
  http://www.squarefree.com/securitytips/web-developers.html
• Great explanation of how to validate:
  http://shiflett.org/articles/foiling-cross-site-attacks
• XSS Cheatsheet:
  http://ha.ckers.org/xss.html