Developing for W3C Compliancy

What is W3C Compliancy?

The W3C (World Wide Web Consortium) was established around 1994 with the aim of standardizing the internet to make it compatible with every other system on the planet. Since 1994, the W3C has developed and more than ninety W3C Standards. (known as W3C recommendations). that are used to ensure cross system compatibility for things like web sites.

In regards to web development, any language you can think of probably has a W3C Recommendation that can be used. HTML, CSS, XHTML, XML etc all have W3C standards.

The W3C doesn't just write standards for web developers though. Browsers these days have to be written that follow the W3C guidelines in order to support W3C compatible web sites. Internet Explorer is one of the few browsers that break the W3C Recommendations which means that more often than not, W3C compatible sites need to employ hacks to work around Internet Explorers buggy implementations.

W3C is totally optional, but it is widely believed that your site SHOULD be W3C compatible in order to maximize your page views etc.

This document gives a brief explanation of how you can make your site W3C compliant. Incidentally, this web site is W3C Compliant in Both HTML 4.01 and CSS, as you can see from the buttons at the bottom of the page.

Clicking on the buttons will take you to the W3C's validate tool and tell you if the page you are viewing is Compliant with the relevant standards or not.

Testing for W3C Compliancy

How do you know when the page your writing is W3C Compliant? The W3C web site has a number of Validator tools for various languages that test your web page or document, and tells you whether it has passed as Compliant or not. If not, it will tell you the problems with your document, where they are, and what needs fixing. Its fairly straight forward.

Quick Note: Internet Explorer and the W3C

Internet Explorer is the bane of all web developers existence. It is by far the most used browser around the world, (I still use it over any other despite its flaws), but Microsoft have made it a pain to develop cross platform web sites.

When building Internet Explorer, Microsoft avoided following the W3C guidelines for compliance, (especially with CSS), and because of this there are a lot of sites on the internet that look fine in Internet Explorer, but they don't display as they should in other browsers. IE does follow some of the guidelines, but a lot of it has bugs and doesn't pass as a W3C Compliant browser.

People new to web development assume that Internet Explorer is the best browser to design for and its easier. I have to admit, it is easier to build sites for IE than a W3C compliant browser, but that's not the point.

In order to Develop your sites to be W3C Compliant, you really MUST test your sites on a W3C Compliant Browser such as FireFox. Once your site is displaying correctly in a W3C Browser, you can apply CSS hacks to make it work properly with Internet Explorer. DO NOT DO THIS THE OTHER WAY AROUND!

Basic Guidelines for HTML 4.01 Transitional W3C Compliancy.

With the W3C Recommendations, there is a lot to take into account when developing a site that will end up as compliant depending on which language is being used.

This section focuses on the basics of developing a W3C Compliant HTML page, and highlights the key things to remember. Some of the rules are common to other languages as well.

Keep tags as lowercase
This isn't actually a W3C rule for HTML 4.01 pages, but it is for the XHTML standard and its a good coding style to adopt.
Images MUST HAVE alternate text
When using images in your HTML 4.01 document, you must ensure that you specify some alternate text using the alt property of the <IMG> tag. for example:

<img src="w3c.gif" alt="The W3C Logo">
Structure is Everything
To qualify for W3C compliancy in HTML, you must ensure that your documents are properly formatted and well written. There are rules that dictate which tags can be nested, and what other tags they can be nested in. An example of this is that a Heading Tag (<h1>) CANNOT be nested inside a Paragraph Tag (<p>).

Please refer to the W3C HTML 4.01 Specification for more information regarding tag nesting.
Illegal Tags
There are some tags of the HTML 4.01 which, although they may work, are flagged as invalid or deprecated when conforming to the W3C Recommendation for HTML 4.01. An Example of this is the <MARQUEE> tag.
Illegal Attributes
There are quite a lot of illegal attributes that people use when designing sites that work with Microsoft Internet Explorer. This was Microsoft's attempt at making things easier for the developer, and it has succeeded in one sense because novice developers can get away with a lot of things if they do not want their site to be compatible with other browsers.

One way they have accomplished this is to invent their own properties for certain elements, such as the 'bordercolor' property for the <table> tag. Using this property will make the border of the table coloured in Internet Explorer, but it will look normal in any other browser. This also breaks W3C Compliancy because it is an Attribute that does not exist in the HTML DTD.

This document is only very brief and probably isn't the best source of information about the W3C. It's only intended as a quick peek into the world of Web Standards. For more information please visit the W3C Web site at http://www.w3.org