What does valid xhtml mean

The content is enclosed by the elements. How this content is displayed is determined by the elements and only displayed by the browser. There are three types, each with certain advantages and disadvantages, transitional, strict, and frameset.

The basic framework of an XHTML file must conform to the rules exactly, otherwise it is not WFF well-formed formula , which is valid source code that meets the requirements of language and document definitions and can be read by a browser. Important differences between XHTML and HTML are, for example, the XML declaration, the document type definition, it is in lowercase, the exact compliance with the basic framework, and the fact that every open element must be closed again.

Use the following markup as a template to create a new HTML document using a proper Doctype declaration. See the list below if you wish to use another DTD. This means that in many XML languages, doctype declarations are not necessarily useful. The list below is provided only if you actually need to declare a doctype for these types of documents.

This is a statement of fact. Maybe I should have just used this paragraph for the post. The post does not suggest that everyone please goes ahead and switches to HTML and starts omitting tags. It does not deal with scripts or images or other things you should of course pay attention to as well when it comes to performance, not at all.

And it does not target education or outreach either. The only relevant factor for your decision is performance, and the conclusions you draw from that are genuinely interesting. Has anybody ever worked on such a thing? On December 21, , CET , Joe Clark said: I think the bigger advantage is not forcing neophytes to type every single thing in lower case, which everyone screws up from time to time. Every XML document, with no exception, follows these rules.

With so many browsers out there each doing different things, the more standardized your code, the better chance your stuff will function on all browsers. But if you really want to save a few bytes here and there by not closing out your BR tags, more power to you.

XHTML are those who give excuse for other forms of invalidity or failure to do due diligence to the craft. What am I missing? Or is that being pedantic now? Ash: there was a case that browser could do incremental rendering for the HTML documents, but had to wait for the XHTML document to be loaded fully before rendering it.

Not sure if that is still the case though. On December 23, , CET , Niels Matthijs said: Just wondering, but speaking about performance only as this seems to be the point of the article.

Html is more or less a mess when it comes to closing tags, so it seems a little harder to process and to get things as intended by the author? I know they are doing different things but why do they need to be like foreign languages to each other. Every bit helps. Simple is faster. HTML is loose and forgiving, why?

Because it was defined for humans to write it. XHTML on the other hand is more redundant and something more geared for a machine to produce.