With Or Without X

Most of my web design and programming skills are self-taught. WYSIWYG editors, like Dreamweaver, helped me make pages without editing code. After a while I had the desire to hand code my sites. That helped me to learn standards based coding while separating the presentation and layout with CSS.

I have always referred to the web content as HTML. I have noticed, however, some sites, and blogs too, say XHTML valid. This is similar to my RSS dilemma, in that I’m not sure what the benefit of XHTML is. I could use some insight in this regard.

What is different between HTML and XHTML, and should I consider using the latter instead?