What is the recommended xhtml version to use these days according with w3.org?
I don´t know but it seems the last recommendation is xhtml 1.1.
But not sure.
The most recent version of XHTML to reach Recommendation status is 1.1.
HTML 5 has an XML serialisation and is at Candidate Recommendation status.
Related
Why is XHTML called "eXtensible" (the X in XHTML)? Can we, as individual web developers actually extend it?
What separates it from ordinary HTML?
Well, firstly, things have moved on somewhat, and XHTML isn't really a thing anymore. HTML5 isn't parsed as XML, and XHTML 2.0 was of course cancelled.
Despite that, it's possible to use XHTML if you use the application/xhtml+xml mimetype, just be aware of the various shortcomings of that (any error = yellow screen of death, older IEs don't render anything at all).
For a new project, use the HTML5 doctype and serve as text/html. XHTML can be considered as a failure for many reasons.
Anyway, with XHTML you can do things like this:
<!DOCTYPE html SYSTEM "http://example.com/my-xhtml-custom.dtd">
<html xmlns='http://www.w3.org/1999/xhtml' xmlns:custom="http://example.com/" xml:lang='en-US'>
then copy http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd and edit it how you like, and put it where we referenced earlier.
The w3c have a lot to say about this, specifically:
Don't do this! Documents need to have a meaning as well as correct
syntax. SGML and XML only define syntax. HTML and XHTML define
meaning. If you add elements that aren't defined by a standard, only
you yourself know what they mean. And in 20 or 50 years, even you may
not know it anymore…
Of course, you can experiment, for example to work on future Web
formats, but other than that you should not use proprietary elements.
Nowadays, we thankfully have HTML5 which dropped all this XML stuff (no one was using it and it adds a lot of complexity). It's not extensible in the same way, but that's probably a good thing!
All modern browsers understand HTML, so what is the point of being XHTML compliant other then writing more characters found on the far right side of the keyboard.
There is no point that I can think of. The W3C has canceled XHTML 2.0, although there is supposed to be an XHTML5, which I guess is HTML5 for masochists. Originally XHTML was going to lead us into the world of "correct" HTML documents, but it generated as many (or more) problems than it ever solved.
We validate against either HTML 4.01 Transitional or HTML5 (to the degree that you can do that). That plus clean CSS gives you about the best you can shoot for.
XHTML was originally supposed to be a "next generation of HTML", as well as a stricter version of HTML (which would cause failures if any error showed up in the page). Due to a variety of loopholes and any number of other issues with XHTML (such as pages serving up the wrong mimetype), hardly any pages are actually XHTML, they're just HTML with some extra characters.
Eventually, HTML5 was proposed, w3c split into two groups, then the people working on XHTML 2.0 switched to something better (HTML5) and now everyone is talking about HTML5 taking over everything.
For a longer version (with far more detail), check out this chapter from Dive Into HTML5: http://diveintohtml5.ep.io/past.html
According to http://www.dev-archive.net/articles/xhtml.html, one of the reasons XHTML was created was:
to add the XML ability to extend the language through namespaces. This will make it possible for an author to express more structures and richer semantics than is possible with HTML today. In effect XHTML inherits the possibility of supporting more than one language — instead of extending HTML in a monolithic fashion, XHTML can be extended through modules, where each module define a specific subset of the language.This, theoretically, means extension of the language can be done without the need for a browser upgrade.
XHTML is meant to make the use of XML–based languages in end–user applications such as browsers easy, but can also be used for various data processing and storage purposes in situations where the web is only one of several channels. XHTML take advantage of the extensibility of XML to support multiple namespaces and through them languages.
That article also notes that for most people this won't be useful:
Recommendations
If you don’t have any specific need to deliver XML–based structures to the client, e.g. due to mixing namespaces such as having MathML content in your pages, using Ruby (XHTML 1.1) or techniques such as ACCESS (XHTML 1.2) then consider whether you won’t be better off simply by using HTML 4.01 Strict.
Edit with additional thoughts:
I forgot to mention the point I popped in here to bring up too - XHTML can be more easily manipulated into other languages using XSL transforms.
I'm refactoring a .Net web application that is in
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
Right now the approach is just to aim for the stars and go for the latest doctype just because it's latest, I would like to make a wiser choice and target a specific one and for good reasons.
There are similar questions existing but the answers might be outdated now.
What is the difference, advantages, disadvantages between standards and quirks mode, what are some quirks I may run into with differently set doctypes?
I have been told that an XHTML doctype is preferable to integrate AJAX since the UpadtePanel serializes it and to do so needs to have a XHTML do type, to what extent is this true?
And for browser compatibility, in which direction are browsers going in terms of DOCTYPE, is there a common thrend or do they differ?
HTML5 doctype, which is
<!DOCTYPE html>
XHTML is largely dead as a standard, and never was implemented correctly in most cases.
The new thing is HTML 5.
<!DOCTYPE html> is what you use to specify it. That's it. No DTD name or URL or whatever.
If you're using something that likes XML, like .net, then you might want to use XHTML. But don't do it for any other reason; XHTML never was really popular as a standard, or at least it was almost never used correctly.
Any Doctype:
HTML 4.01 or XHTML 1.0
Strict or Transitional
served as html (not html+xml) should be OK. There's no such thing as a better doctype, you just have to choose one filling your needs and then stick to its rules.
Avoid Frameset, but if you've to, use the title attribute to describe the role of each frame to a screen reader user (same with iframe btw).
Quirks mode (no Doctype) is a PITA, avoid it at all cost. This was OK 8 years ago.
No XML prologue unless you're serving html+xml (good luck with that! If you like complicated things when it's not needed, that's your choice)
If you are forced to use attributes that are forbidden in Strict mode (target="_blank" for example) than use Transitional mode: this is why it was created! And please indicate to your users that the link will open in a new page, whether in the text of your link or in its title. This is important from an accessibility point of view.
HTML 5 is the next big thing, we're waiting for it but as long as it won't work in every browser (I mean IE without JS) it's not advisable to use it in "serious" public sites. Is it even a Draft? What if entire part of it are rewritten in a couple of months?
My web agency uses it for its website but we won't use it on a client site anytime soon: it's just too soon.
Sidenote: I often see catch phrases like "a modern website in HTML5 and CSS3" implying that CSS3 is made for HTML 5. CSS3 has nothing to do with HTML5 and can already be used, as long as it degrades gracefully on old browsers.
You can design HTML5 with CSS2.1 or HTML4.01 Transitional with the latest CSS3 animations that only work in webkit nightlies, no problem.
Whatever you choose, make sure your MIME-Type is compatible with your DOCTYPE
The browser will use the MIME-Type (the HTTP Header ContentType) to determine how to treat your page. For example: A DOCTYPE of XHTML 1.1 Strict served as ContentType Text\HTML is parsed as HTML.
DOCTYPE is important, but largely irrelevant if the wrong ContentType is used.
Browsers have never actually used DOCTYPE to determine the markup language of your document (they use HTTP Content-type instead), so which DOCTYPE you chose was never hugely relevant - just as long as you are using a valid DOCTYPE of some description. Whichever you choose is up to you.
If you're writing HTML, <!DOCTYPE html> is the shortest to type, and puts all browsers into standards mode (which is what you want).
If you're writing XHTML, <!DOCTYPE html> is also perfectly legitimate (XHTML actually requires no DOCTYPE at all, as it relies entirely on HTTP Content-type, but there's no harm putting a DOCTYPE in for portability.
Don't use <!doctype html> - while this is technically valid HTML, it's invalid XHTML so will break if you ever try to parse your page as XML.
Slightly OT sidenote: Some people here have commented that XHTML is a "dead" standard - this is false. XHTML has been integrated into the upcoming HTML5 spec. The spec is entitled "HTML5: A vocabulary and associated APIs for HTML and XHTML"
See:
http://www.w3.org/TR/html5/the-xhtml-syntax.html
http://html5doctor.com/html-5-xml-xhtml-5/
Is there a W3C document type available with both XHTML 1.0 transitional support and RDFa support?
I am aware of the XHTML+RDFa 1.0 (http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd) DTD but that is XHTML 1.1 which is not compatible with my current website. It seems that there is also a HTML4+RDFa 1.0 (http://www.w3.org/MarkUp/DTD/html4-rdfa-1.dtd) DTD available.
My main reason for not serving XHTML 1.1 is Internet Explorer ofcourse, although I could probably serve it as text/html for the IE users if there is no other way.
I don't believe there is such a DTD, no.
HTML is becoming more and more fragmented and creating DTDs for every possible combination is not going to be practical. HTML5 is not SGML based and effectively gives up on DTDs. In future, validators are probably going to have to change so that they call in component collections like RDFa and ARIA, and indicate in their results which collections are required to allow each particular piece of mark-up to be conforming.
Unfortunately, we're really at about the transition point currently, so there's no clean solution to your problem. However, a certain amount of pragmatism will get you a long way.
Now, XHTML+RDFa 1.0 may be defined by DTD as an extension of XHTML 1.1, but it isn't actually XHTML 1.1, nor is it XHTML 1.0 transitional or strict, or indeed anything other than "XHTML+RDFa 1.0".
So you can take a pragmatic serving approach. Consider the HTML5 attitude to this. It says that anything you serve as text/html is an HTML serialization of the object model, regardless of any DOCTYPE that you declare. This is in practice what browsers do anyway.
Similarly, anything you serve with an XML content type such as application/xhtml+xml is an XML serialization. Those parts of the XML that have the xhtml namespace constitute XHTML.
So, in practice, you can serve your XHTML+RDFa 1.0 as text/html or application/xhtml+xml without any difficulty, provided that the mark-up meets the requirements for polyglot documents.
That leaves the validation. Leaving aside RDFa, is there any mark-up that you're using that's conformant XHTML 1.0 Transitional but not conformant XHTML 1.1? If so, do you care enough about perfect validation to either change these, or to back away from using RDFa? Presumably you're using RDFa for your users benefit, while validation is essentially a convenience tool for yourself.
I faced a similar situation recently, when I decided to add ARIA attributes to my XHTML 1.0 pages. I decided that Accessibility trumps Validity, and I would add the attributes and forget about ensuring my pages were 100% valid.
In reality unless you are concerned with the DTD implementation there are almost no differences between the various XHTML versions and there's almost never a valid reason not to use XHTML 1.1. In what way is your website dependent upon 1.0 transitional? If you can get your site valid with 1.0 strict then moving from that to 1.1 shouldn't cause problems because essentially the only difference is the modularized DTD, which really has no drawbacks to it.
If you're still struggling with the philosophical problem of XHTML MIME I wouldn't worry because conceptually serving the wrong media type with the better organized 1.1 DTD is no more of a crime than with 1.0. The reason RDFa is implemented as it is is because adding the RDFa module to the XHTML 1.1 DTD only involves adding a few lines to the main module. Doing that to the 1.0 DTD would be harder and not as clean.
Some other things to consider are that the XHTML 1.1 second edition spec includes an XML schema implementation. Also, the latest XHTML+RDFa 1.1 working draft finally drops the (stupid) requirement for specifying a doctype altogether, so you could use schema-only validation. This would work out really well if you can figure out a way to use XML/XHTML mimetypes because no doctype declaration is required in order to get standards mode rendering on browsers which support it (all of them but IE8 and below).
I am in a bit of a dilemma: I know XHTML 1.0 really well and HTML really well. But what markup language should I use in my latest PHP application? XHTML 1.0 or HTML5?
Also which would be future proof?
And finally if I was to build a normal site, what language would be best to use now?
For the time being, I would advise you to stick to HTML 4 (and not XHTML).
As mentioned, if HTML5 is the future way to go, it is not supported enough for now.
Regarding XHTML vs HTML, this is a bit a trollish subject, but I do agree with Jeff Atwood and James Bennet that XHTML is just not worth its pain.
XHTML is nice, but it's really only practical as the output of some sort of XML-based process. Stick to HTML 5 for now.
Stick to HTML 4.
In most cases, generating HTML Compatible XHTML is more trouble than it is worth, while HTML 5 is still subject to change and the new features in it are poorly supported.