It really is an excellent video – really creative and informative – well done!

I now have an idea of Web 2.0 and what it means to me and the part that I have to play!

Thanks

Really nice video, although I have one gripe: Separation of content and presentation is nothing new with XML. It has been the goal in HTML since CSS came around. XHTML 1.0 has all of the same elements and attributes that HTML 4.01 has, including the deprecated stylistic stuff. XHTML 1.1 is out of the picture for reasons I’ll explain below. In fact, if you plan to support Internet Explorer, XHTML has absolutely no benefit over HTML, because, whether you know it or not, you’re telling the browser to treat it as if it were HTML.

The proper content-type header for XHTML is “application/xhtml+xml”, but Internet Explorer completely chokes on this. Because of support problems in Internet Explorer and various search engines and other user agents, most XHTML pages on the Web are sent as “text/html”, which instructs browsers to treat the page not as XHTML, but as regular HTML. As long as you follow the crippling limitations in Appendix C of the XHTML 1.0 specification (not allowed in XHTML 1.1!), most popular browsers will let you get away with this.

This works primarily because most popular browsers just happen to not support a little-known shorthand feature of HTML/SGML called “null end tags”, which, if supported, would conflict with the “/>” syntax and pollute these XHTML pages with garbage “>” characters everywhere. Instead, they generally interpret the “/” character as junk and ignore it, so “<div />” is literally treated as “<div>” instead of “<div></div>” as an XML parser would see it.

Because the browsers treat the page as HTML, you get absolutely no benefit from using XHTML over HTML, and you instead *promote the non-standard behavior* of ignoring null end tags. Meanwhile, if you don’t thoroughly test what browsers *would* do if your page were sent as application/xhtml+xml, you’re also running the risk of completely breaking your page when a browser for some reason decides to try parsing the page as XML (which it may do if, for example, the user agent wants to store the document locally and loses the content-type header information in the process).

In short, the idea that XHTML as it is used today is somehow better than HTML is simply an illusion, since most browsers are treating the two identically most of the time.

I’d like to add emphasis on “as it is used today”, since XML does have many potential benefits which are inherited in XHTML when it’s sent as application/xhtml+xml. But until correct support for XHTML comes about in Internet Explorer and the other lacking user agents, using XHTML the wrong way will just make it more difficult to promote the correct way when that time comes.