Validating asp.net with W3C standards

Doctype:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

I didn’t code this, which is half my battle. I don’t even have the back-end to this code. I have the majority of the pages, all of the CSS, images, etc, for the most part. Makes life a little difficult.

I code with HTML5 standards, this is not my idea of fun. This has been my ten months of hell lol