How to determine the right Doctype?

Question

I am currently working on a website and heard that there are actually different Doctypes that I can include at the start of the page. What are they used for and which one should I use?

Answer 1

The DOCTYPE declaration determines what rule set you are using for your HTML. This helps the browsers understand what the tags mean and how to use them.

Which one you should use depends on your personal preference, but this site - http://www.w3.org/QA/2002/04/valid-dtd-list.html - will help you choose the one right for you.