Hey guys, after a few researchs on this subject; and obviuosly your help; I have comprehended a little bit better about the strict vs transitional. Strict: anything deprecated (condemned) or made obsolete is not allowed, whereas, Transitional allows deprecated elements in the markup. I like how Tedester adressed "Strict mark-up is more solidly future-proof". It's true, due to a inconsistences between browsers. So I'm going to stick with transitional DTD. Thanks guys!