Validation is a process of checking your documents against a formal standard, such as those published by the World Wide Web Consortium (W3C) standards for HTML and XML-derived Web document types. It serves a similar purpose to spell checking and proofreading for grammar and syntax, but is much more precise and reliable than any of those processes because it is dealing with precisely-specified machine languages, not with nebulously-defined human natural language.
It is important to note that validation has a very precise meaning. Unfortunately the issue is confused by the fact that some products falsely claim to "validate", whilst in fact applying an arbitrary selection of tests that are not derived from any standard. Such tools may be genuinely useful, but should be used alongside true validation, not in place of it.
If you would like to make your web pages usable by everyone, we feel it is important that you emphasize standards compliance. By complying with existing standards, rather than relying upon browser specific extensions and hacks, you can make sure that the web sites you design will be readable by all browsers supporting those standards, not just the ones you have time to test it on, and that your page designs won’t break when new browsers and versions come into existence. HTML tags that go through the standards process are evaluated more thoroughly and designed for graceful degradation on older browsers.
"Graceful Degradation" is an important principle in Web design. It means that, when you put in features designed to take advantage of the latest and greatest features of newer browsers, you should do it in a way that older browsers, and browsers letting users disable particular features, can "step down" to a method that still allows access to the basic content of the site, though perhaps not as snazzy in appearance.
We choose to use the World Wide Web Consortium (W3C) as the focal point for our web standards – see their pages (and some other useful resources) for more details:
- W3C – The World Wide Web Consortium (Information on current and proposed HTML specifications)
- HTML 2.0
- HTML 3.2
- HTML 4.0
- Web Design Group – Standards for HTML Authoring for the World Wide Web
Testing and Validation
In order to make pages that are viewable by all, it is very important that you test and validate your pages.
Nobody has time to test pages in all the browsers that are out there, but by making sure your HTML doesn’t have mistakes in it, you can make sure that no browsers will choke on errors in your HTML. Browsers are fault tolerant by design, but to different degrees, and so while one browser may recover from errors in your pages without you noticing a difference, those same errors may cause another browser to render a page with noticeable problems.
One excellent example of this is what happened when Netscape 2.0 came out. Previous versions of Netscape allowed you to skip a matching quote in a link with no ill effects, but when Netscape 2.0 came out, it was more strict, and wouldn’t close the link till it found the next quote. A lot of people had to go hunting through their many HTML pages for missing quotes and fix them when this happened (me included :). So make sure to validate your pages as you’re writing them so you don’t have to go back and fix them later.
There are many excellent sources on the Internet to validate web page code. Some are available for download and are platform specific, while others have web based interfaces, such as:
For more information about the value of validating web pages, see:
In addition to validating your pages, it is also a good idea to test in a representative selection of browsers to see if there are any problems with your pages that you didn’t catch in the validation process. It is a good idea to test in Netscape and/or Internet Explorer since those browsers are used by a sizable portion of the Internet. In addition, you should also test in a text-only browser, like Lynx, and you should probably also select another browser for testing. Testing on multiple platforms, browser versions, color depths, and resolutions is also a good way to find problems that you may otherwise miss.
Several of our clients have decided to "maintain their website" which we actually think is cool. However in spite of the warnings and suggestions we have offered they may have possibly modified the code to where it is not in "specification"