Monday, April 30, 2007
HTML Standards Compliance - Why Bother ?
Most pages on the web don't comply with the W3C's HTML specifications. In some cases this is because their authors wanted to take advantage of proprietary extensions; but in many other cases, the pages could easily have been made more conformant without any problem. This article explains what the issues are, and why you should and how you can, bring your pages into compliance with the HTML standards.
The fundamental reason for HTML standards compliance is to ensure that you use only those elements and structures that are likely to be understood by the widest range of user agents. It's like English - if I were to speak my parent's dialect (East Anglian) most other English speakers would not understand everything I say. Similarly, if you use proprietary dialects of HTML, some user agents won't understand everything you write. There is however, a standard for HTML which the browser makers say they support, and validation points out the divergences in your HTML source. By adhering to the standards you maximise the accessibility of your work to the widest range of user agents, and therefore, users.
Some people take the view that checking their pages in the two major browsers is validation enough. Close, but no cigar.. There are still dialect variants even within a single make of browser, across the different versions and platforms - let alone between the two. And why neglect all the other user agents such as text-mode browsers, text to speech synthesizers, search engine spiders and other robots, site analysis tools, etc? Perhaps, because it's too much extra work? Maybe, but most of the compliance errors I've seen are trivial to fix, e.g. missing ALT attributes (not tags!) in IMG tags. Others might be harder to understand and fix but practice overcomes this, and in the end your "inner satisfaction" is in knowing that you've done a good professional job that can be appreciated by all.
Sites often use a "browser sniffer" to detect which browser you're using, and then serve you a page specifically optimized for your browser. As the WaSP says in their mission statement
"Creating multiple versions of the same Web page because of incompatibilities among browsers is wasteful and self-defeating for Web developers and their clients. The alternative is to try to resolve the incompatibilities by often complicated workarounds that are costly for developers and their clients - at the cost of preventing Web pages from being flexible enough to be used by emerging television-based and PDA-based browsers."
HTML standards are designed to remain as backward-compatible as possible while also attempting to be as forward-compatible as possible. In particular, they are designed so that older conformant pages are not too likely to break on newer browsers, and future conformant pages will "gracefully degrade" on older browsers. Choosing to adhere to any proprietary format, or none in particular, is very likely to cause a site to look worse under older browsers, or future browsers, than if the standards were followed. According to W3C's HTML 4.0
"Most people agree that HTML documents should work well across different browsers and platforms. Achieving interoperability lowers costs to content providers since they must develop only one version of a document. If the effort is not made, there is much greater risk that the Web will devolve into a proprietary world of incompatible formats, ultimately reducing the Web's commercial potential for all participants.
Each version of HTML has attempted to reflect greater consensus among industry players so that the investment made by content providers will not be wasted and that their documents will not become unreadable in a short period of time.
HTML has been developed with the vision that all manner of devices should be able to use information on the Web: PCs with graphics displays of varying resolution and color depths, cellular telephones, hand held devices, devices for speech for output and input, computers with high or low bandwidth, and so on."
The solution is for developers to adhere to the HTML standards, and for the browser makers to support them fully before adding their innovations.
from "http://wdvl.com/Authoring/HTML/Standards/"
by "Alan Richmond"
The fundamental reason for HTML standards compliance is to ensure that you use only those elements and structures that are likely to be understood by the widest range of user agents. It's like English - if I were to speak my parent's dialect (East Anglian) most other English speakers would not understand everything I say. Similarly, if you use proprietary dialects of HTML, some user agents won't understand everything you write. There is however, a standard for HTML which the browser makers say they support, and validation points out the divergences in your HTML source. By adhering to the standards you maximise the accessibility of your work to the widest range of user agents, and therefore, users.
Some people take the view that checking their pages in the two major browsers is validation enough. Close, but no cigar.. There are still dialect variants even within a single make of browser, across the different versions and platforms - let alone between the two. And why neglect all the other user agents such as text-mode browsers, text to speech synthesizers, search engine spiders and other robots, site analysis tools, etc? Perhaps, because it's too much extra work? Maybe, but most of the compliance errors I've seen are trivial to fix, e.g. missing ALT attributes (not tags!) in IMG tags. Others might be harder to understand and fix but practice overcomes this, and in the end your "inner satisfaction" is in knowing that you've done a good professional job that can be appreciated by all.
Sites often use a "browser sniffer" to detect which browser you're using, and then serve you a page specifically optimized for your browser. As the WaSP says in their mission statement
"Creating multiple versions of the same Web page because of incompatibilities among browsers is wasteful and self-defeating for Web developers and their clients. The alternative is to try to resolve the incompatibilities by often complicated workarounds that are costly for developers and their clients - at the cost of preventing Web pages from being flexible enough to be used by emerging television-based and PDA-based browsers."
HTML standards are designed to remain as backward-compatible as possible while also attempting to be as forward-compatible as possible. In particular, they are designed so that older conformant pages are not too likely to break on newer browsers, and future conformant pages will "gracefully degrade" on older browsers. Choosing to adhere to any proprietary format, or none in particular, is very likely to cause a site to look worse under older browsers, or future browsers, than if the standards were followed. According to W3C's HTML 4.0
"Most people agree that HTML documents should work well across different browsers and platforms. Achieving interoperability lowers costs to content providers since they must develop only one version of a document. If the effort is not made, there is much greater risk that the Web will devolve into a proprietary world of incompatible formats, ultimately reducing the Web's commercial potential for all participants.
Each version of HTML has attempted to reflect greater consensus among industry players so that the investment made by content providers will not be wasted and that their documents will not become unreadable in a short period of time.
HTML has been developed with the vision that all manner of devices should be able to use information on the Web: PCs with graphics displays of varying resolution and color depths, cellular telephones, hand held devices, devices for speech for output and input, computers with high or low bandwidth, and so on."
The solution is for developers to adhere to the HTML standards, and for the browser makers to support them fully before adding their innovations.
from "http://wdvl.com/Authoring/HTML/Standards/"
by "Alan Richmond"
# posted by Alex @ 07:42 
