What are the things to consider what kind of doctype should be used in a website? I've always used XHTML 1.0 Transitional and I'm slightly aware there are differences semantic differences between doctypes, so I wonder if anyone would shed some light over this particular decision. Thanks!
The primary diferences between Strict and Transitional relate mainly to the formatting elements such as
<strike> and attributes like
bgcolor. This functionality is allowed in Transitional, but not in Strict and is largely used to help developers make the transition between HTML 4.01 and XHTML 1.0 by making some of those elements available.
That being said, XHTML best practice is to have only functional markup in the .html document and to have all styling located in a stylesheet, so my recommendation would be to move inline with XHTML standards and separate your markup and styling.
There is a 24 Ways article on the differences between the Transitional and Strict doctypes here.
When creating new web pages, there is little to question or understand beyond knowing you are to use a strict doctype. New pages should not be using deprecated markup so that throws out every other version. The only decision to be made is whether to use the xhtml or html doctype and that is controversial.
My opinion? Since few, if any of us, actually serve xhtml as xhtml, use the html strict doctype and quit thinking about it. Of course, there's the html5 doctype, too, but I don't know if you want to get into that.