Once you've written a web page, you can upload it to an HTML
validator. This site, run by the web's standards body, will
check that your site is valid ('correct') HTML, and give you
some idea of how to fix it if it isn't. This is an essential
step in the development of any website - as vital as running
your text through the spell checker - but whenever I recommend
it there's always someone who wonders why it's so important.
Well, here's why.
You Know Your Code is Correct
If your code validates, then it's correct, and therefore very
likely to work as intended on every web browser out there. If
you don't validate your pages, then you might find that people
who visit your site with less forgiving browsers see nothing at
all. Correct code is more likely to display correctly on many
different browsers, because it puts them into their 'standards'
mode. If code is even slightly incorrect, many browsers will use
a different way of displaying it, known as quirks mode, which is
designed to handle old and bad HTML, takes a long time and may
make your page end up with errors you didn't expect.
Without web standards, you end up going back to the bad old days
of having to develop entirely separate web pages for different
browsers. Validating by the standards ensures that all working
browsers can view your content - if they can't, the fault's with
them, not with you.
Search Engines Like Valid Pages
When it comes time for a search engine to add your page to its
results, it's going to have a much easier time understanding the
page if it's been validated. This will often get you a higher
ranking in the results, which means free visitors for you. If
your page isn't valid, search engines will often miss keywords
in your pages or not understand your navigation, and may list
nonsensical parts of your code under your site's name in the
search results - not exactly helpful to potential visitors who
want to know what your site is about.
Mobile Devices
More and more people are accessing the web using mobile devices
like mobile phones and PDAs, and these devices have a lot of
trouble with code that isn't valid. Because they have limited
processing power, it would take them a very long time to try to
untangle invalid code - they will simply strip out the
formatting and do the best they can with it. Writing valid HTML
lets users with mobile devices see your pages as you intended.
Disabled People
When you write valid code, it becomes much easier to view with
things that aren't web browsers, such as screen readers.
Technology for disabled people doesn't tend to be as forgiving
as web browsers, so having valid code is important when it comes
to working with these programs.
Future-Proofing
Before your code will validate, you need to explicitly say which
version of HTML you had in mind when you created it. This
future-proofs your code, as each version of the standard doesn't
change once it's been decided on: a valid XHMTL 1.1 page will
always be a valid XHTML 1.1 page, even if everyone else has
moved on to XHTML 5. Once you've validated your site once, you
can put it on the web and be confident that people are going to
be able to read it for a long time to come.
Finding Errors
If there's a mistake in your website's code, validation gives
you an easy way to track it down and fix it. Before validation,
people had to test their site after each change and look
carefully to make sure that nothing had gone wrong. Writing
valid code lets you use programs that will examine what you've
written and point at the exact place where the code doesn't
validate.
A List of Validators
Here are a few validators that you can try. Most HTML validators
are online, but there are a few that you can download and use on
your own computer.
The W3C validator: validator.w3c.org
The WDG validator:
www.htmlhelp.com/tools/validator
CSE validator:
www.htmlvalidator.com (downloadable)
WebTechs validator:
www.webtechs.com/html-val-src
Doctor HTML:
www.doctor-html.com (downloadable)
You might also be interested in visiting the W3C's main site at
w3c.org, as well as the Web Standards Project at
www.webstandards.org.
About the author:
Information supplied and written by Lee Asher of Eclipse Domain
Services
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