Why Validate Your HTML ?
These are the two main camps in the validation debate.
| It Looks Great in the Main Browsers |
Make It Look OK in All Browsers |
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"Web developers are on the practical side of things. We do what we can
to develop web sites that are usable by as many as possible. The
practical side of the story is that the majority of web users use
Netscape and most of the rest use Microsoft's Internet Explorer.
Web developers must make conformity to the standards that NS and MSIE
uses a higher priority than the standards put forth by the W3C."
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"The web is supposed to be device-independent. Documents should render
properly on all user agents, including text-only browsers and HTML to
speech convertors. HTML is not a presentation language, it's a markup
language and all documents should conform to the W3C standards.
Your documents should not use vendor-specific extensions, and might not
look their absolute best in specific browsers - but they'll look OK in
them all."
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Let's look at the issues in a little more depth.
Widest Range of Accessibility
Standard HTML is accessible to the widest range of users,
regardless of their choice of browser.
Following the
W3C
standards should ensure the widest accessibility to your work,
i.e. all standards-conforming browsers should render your
pages reasonably alike.
The alternative is Babel, which is currently the
state with dynamic HTML.
Your pages are being viewed in many different environments, such as
Netscape, MS Explorer, Lynx, HTML to speech or braille generators.
You're on the World Wide Web;
you cannot say, unless you are on an Intranet or catering only to a
select group with a known platform, what browser or 'user agent', and
what version, is being used, and by whom (e.g. the visually disabled).
Some sites insist that you must use NS or MS to view their pages. And
they may, but they are cutting off those who for whatever reason choose
a different browser. So the point of an HTML standard
is to guarantee a common basis for compliant browsers.
It's like electrical standards - you should be able to plug in your
hair dryer anywhere in the USA and have it run
(but not anywhere in the world). Pages validating to HTML 3.2 should
be viewable by the widest possible range of browsers and users.
Browsers Can't Correct All Errors
HTML has
rules that you need to follow otherwise programs such as browsers
might not be able to figure out what you intended.
You may also catch errors that aren't uncovered by eye-balling the
document in a browser, e.g. extra or missing quotes on a URL may make
the link invalid but might still be presented OK in your browser.
Or suppose that you misspell some attribute names, e.g. HIEGHT or
WITDH in your IMG tags. These help some browsers to layout your page
and are a very good optimisation for your users; you might fail to
notice any diference, e.g. because your images are already cached for
you. An HTML validator will catch this.
You won't have the time to test pages in all the browsers,
but by making sure your HTML doesn't have errors, you can make sure
that no browsers will choke on pages.
Browsers are designed to be fault tolerant, but none can gracefully
handle every possible error, and so while one browser may recover from
certain errors without anyone noticing a difference, those same errors
may cause another browser to render a page with noticable problems.
Not All Visitors Can Visualize Your Web Pages
Consider also that graphical
browsers aren't the only programs that might process
your documents. Other programs, such as speaking browsers for the
visually impaired, or search engine spiders or robots
may also be involved, and might not be so tolerant as browsers are, of
invalid HTML; the result could easily be that your document is
incorrectly intoned or misrepresented in the search engines.
Concentrate on Content Instead of Browser Differences
If you are concerned with pixel-perfect rendering of your pages,
you may well want to study the major browsers and insert code to
detect which browser is visiting a page (a 'browser-sniffer') and
deliver a page optimised for that browser. This will add significantly
to your development overhead. However, if content is more important
to you than presentation issues - write to the standards, and
look into the use of style
sheets.
If You Teach HTML, Show That You Understand The Issues
One of the commonest types of posting in the HTML newsgroups is for new
HTML tutorial sites. They usually get the response that they don't
validate and that this raises the question of whether the site is
credible.
If a site claims to teach HTML, you might reasonably expect the site's
pages to validate against some standard. This is too frequently not the
case, and you are left wondering if the author understands HTML well
enough to be teaching it. So my advice to you, if you are looking for a
credible HTML tutorial, is to check its first page using
the W3C's validator
and go elsewhere if it fails. The better sites
make it easy for you by putting a validation button on their pages. In
some cases (e.g. at WDVL) clicking on it performs the validation.
Parlez Vous HTML ?
HTML Checkers
Half a Loaf is Better Than None
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