I've never put a DocType in my HTML pages (actually they are .asp). I just check validator.w3.org/ and found that I need to do that first.
I have checked out several posting here on this topic but they are quite old. There are so so many different doctypes and need to know which to you.
Here are a few they say that are common but I just can't understand all the mambo jumbo. Can someone help me on which is most common and suitable TODAY. I am using HTML and have asp scripts and my page is save as .asp. Please help.
Here are some of the common ones they mention:
1) HTML 4.01 Strict
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
2) HTML 4.01 Transitional.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
3)HTML 4.01 Frameset.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd">
The rest are here:http://www.htmlhelp.com/tools/validator/doctype.html
Also if I use the wrong one, will anything happen or will I be penalized? Please help.