RDFa, Microformats and Microdata provide easy ways to include semantic markup. Are there any other similar technologies ?
Thanks
RDFa and microdata do not do very different things. All three formats do approximately the same thing in different ways, with RDFa and microdata being very similar.
Read Manu Sporny's Uber-comparison of the three for more details: http://manu.sporny.org/2011/uber-comparison-rdfa-md-uf/
RDFa, Microformats and Microdata actually do very different things.
All 3 potentially provide a means to annotate fragments of HTML
RDFa is also a way to publish RDF in an HTML document since there is a formal model for parsing RDFa (unlike the latter).
In addition to the above, there is also MathML and RDFj, the former which is restricted to XHTML resources (and HTML5 resources if I am not mistaken) and the latter, to Javascript/JSON resources or inline script.
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 am really new to this so please forgive the basicness of my question...
I want to learn to design websites and I have a program which I am planning to learn (Dreamweaver CS5) using tutorials from Lynda.com. However on the tutorial it says you should have a good grasp of HTML and CSS before starting Dreamweaver.
I looked at the Lynda.com video for HTML but it is all focused on XHTML. http://www.lynda.com/tutorial/47603
Now I am a bit confused. I heard a new standard was coming in (HTML5). If I learn XHTML - does that mean that I will then have to go back at a later date and learn HTML4 so that I can then catch up and learn HTML5 or will I be able to use my XHTML knowledge and add the future HTML5 code to it?
For example there is a Lynda video on HTML5 but the author says you need a knowledge of html before you can watch it.
Do you think the Lynda.com video on XHTML/HTML is a good place to start or do I need to get a book on HTML4 instead?
If you were starting out now would you learn HTML4 or XHTML?
Thanks
XHTML, absolutely.
Last recommended HTML version was 4.x, and it's from 90s era.
Learn XHTML as much as possible, and try to use strict versions.
I agree with #Matías, if only because of it's strictness which will likely result in cleaner code in the long run. That said, porting from one html version to another shouldn't be too difficult regardless of which one you choose.
I find that when programming the use of XHTML is nice because it allows me to catch errors in my markup at compile time instead of some obscure bug showing itself way later when I modify a page.
The whole lack of XHTML 1.1 support in IE has been a pain, but there are work arounds such as XSL transformations and the such. IE9 has finally added support.
Once (X)HTML5 support becomes strong in the major browsers I intend on using XHTML5 in any web projects I do for work. Supporting legacy IE versions will still be a pain, but it will be manageable.
I would learn HTML4.01, but only because I detest XHTML.
It doesn't matter that much, making the port from (X)HTML x.xx to (X)HTML y.yy is not that hard. You'll have a few pitfalls, but that's all.
On the other hand, HTML5 is quite different and you can start learning it already. It's already happening.
Whatever you learn, make sure you learn the Strict version.
Check this out for future proofing: http://blog.twostepmedia.co.uk/css3-still-novelty-or-usable-in-everyday-web-development/
To the O/P, learn the basics of HTML4 and then get straight onto HTML5, you'll be way ahead of the pack and your websites WILL stand out :)
I would personally work on learning HTML5. By the time you get proficient at it to be good enough to professionally code websites, most of the major browser vendors will have adopted it as the standard.
Remember, web technology moves fast! What's hot today will be obsolete tomorrow, and what's in beta now will be hot tomorrow.
I found this http://headjs.com, a modernizer, here on Stack Overflow, which is used to future-proof web applications. This makes learning and using HTML5 markup a possibility today, so that as browser vendors update their applications, they'll slide right into the HTML5 functionality.
Make CSS apply only for Opera 11?
For a brief summary:
HTML 4.01 is the current standard of markup languages for the internet.
XHTML 1.0 was forked off from HTML 4.01. It introduced greater strictness in validation, more XML-like syntax (eg. <br /> instead of <br>) and XML namespaces for things like MathML (for embedding mathematical equations in pages.... very infrequently used). In theory XHTML allowed people to define their own tags.... but in practice this never happened. In actuality, the only real different it has from HTML 4.01 are the self-closing tags, a different doctype (the header at the top of HTML documents), and a few attributes on the <html> tag.
XHTML 1.1 was a natural progression from XHTML 1.0. It introduced even greater strictness, and enforced things like mime-types for served documents. However, because it declared it was XML instead of HTML, and had to be served to the browser as XML (which Internet Explorer to this day does not support), it never took off.
XHTML 2.0 was a draft recommendation that got scrapped along the way. No-one subsequently uses it.
HTML 5 is the next evolution from HTML 4.01. It adds a lot of new tags, new functionality such as local storage (meaning more web-app type applications are possible), and some other goodies. It comes in two flavours - HTML 5, which uses HTML-style syntax, and XHTML 5, which uses XHTML syntax with self-closing tags (and is not to be confused with XHTML 2, which is dead remember.) It is 'the next big thing' in web markup languages, but is still in draft stage. Some browsers are introducing support for new HTML 5 tags, but legacy browsers have no support.
HTML 5 cannot be safely used in current sites, due to the draft nature of the specification. Some sites are doing so, but those sites can possibly get the whole nature of the language yanked out from under their feet.
HTML 5 is not expected to be a formal recommendation until 2022.
In summary: The current language of the web is HTML 4.01. HTML 5 expands on that greatly, but is not ready for everyday use. And the differences between HTML 4.01 and any flavour of XML, are minimal at best.
XHTML's main benefit, as Matias said, is it's XML compatibility, and also the other way round; I regularly use an XSLT to transform an XML document into XHTML. Although XSLT can output HTML, it's HTML that's compliant with XML anyway.
Strictly speaking, there's no reason you can't write HTML5 that's totally XML compliant; for that reason alone, I'd say go with HTML5, and by writing it so that it IS XML compliant, you also get all the benefits of XHTML.
I am reading and hearing conflicting information on this subject. w3c closed XHTML 2.0 working group and asking us to look at XHTML 5 coming out of HTML5. How is this different from XHTML 1.0 or 1.1?
XHTML5 is defined by means of abstract tree-like elements (i.e. by DOM), unlike previous HTML versions, that were defined by tags, which were tied to SGML representation.
By using abstract elements, document tree can have several representations. HTML5 defines two standard serializations: SGML-like (technically not based on SGML) HTML5 and XML-based XHTML5. You could even invent your own serialization format, for example JSON-based.
XHTML5 is semantically equivalent to HTML5 (i.e. have the same sets of elements, attributes and nesting rules), but expressed in different syntax. It is even possible to construct document that conforms to both HTML5 and XHTML5.
HTML5 is not part of SGML but XHTML is prt of XML which is part of SGML. So you can have empty tags within HTML5 but not within XHTML.
You can extend XHTML with any XML structure as long as you provide a DTD for that format. in HTML5 there are only some extesions like SVG, MathML which you can use.
I really liked XHTML because it is like XML but HTML5 has a lot more to offer beside other XML formats. Just google a bit what Google, Mozilla, YouTube etc. has to offer with HTML5 and how much you can do with pure HTML5+CSS3 and without the need of JavaScript.
HTML5 has the option to be XML-compliant or not, as far as requiring strict entities, closing tags, etc. So if a strict XHTML format is important to you (as it is to me), HTML5 allows for that. But the flip side of this is that when consuming HTML5 documents from other services, you cannot necessarily rely on them to be strict like you could with XHTML.
The best we can do is encourage others to follow the stricter format by adhering to it ourselves and evangelizing it. IMO it helps far more than it hurts.
HTML5 is HTML 4 with some tags added, some tags taken away, a different doctype, and generally, a bunch of new stuff.
XHTML 1 is just HTML 4 with XML-style syntax.
XHTML5 is just HTML5 with XML-style syntax.
(I may be glossing over some XML details there.)
This is strictly an opinion/experience question for research purposes.
I was wondering what coding standards companies have in place now for Web Developers? (Document formats, coding standards, file structures, etc.)
Obviously they all can't be listed, but some major ones would give me an idea.
I hope that company coding standards for Web Developers include W3C standards, but commercial pressures will tend to encourage whatever solution gets the job done.
I would love to be proved wrong in this regard.
The World Wide Web Consortium is the main international standards organization for the World Wide Web.
At the previous (large) company I worked for, there were three main standards that were to adhered to for front-end work:
All HTML would adhere to the HTML 4.01 Strict standards, with the following exceptions:
iframes were to be allowed due to advertising.
The start attribute was to be allowed within lists.
target="_top" was allowed to be used for framebreaking purposes.
These exceptions were codified into a custom doctype document, which is documented here. All work produced was expected to validate against this doctype.
All CSS would validate against the CSS 2.1 standard, with the exception that the * and _ prefix hacks were allowed to be used.
All JavaScript was expected to pass through JSLint without issue (strict whitespace was absolutely not turned on).
We also ran regular code reviews with the expectation that these would allow us to pull out the good work done by our developers and codify this into best practice.
The Web Accessibility Initiative (WAI) is something to be considered as well by any serious web developer: http://www.w3.org/WAI/
Try StyleCI, it supports PHP, JavaScript, CSS, Typescript, Less, SCSS and Vue.js.
You can configure StyleCI to your coding standards too and it can automatically fix your code. We use it on a bunch of projects.