Validating Hypertext Markup Language
Many people might think of the Web as an appliance with a uniform interface that works only from a computer desktop or laptop system. In fact, the Web is used increasingly by mobile access 1, 2 with a variety of Web browsers. This means that a user's Web browser might be in a cell phone, hand-held computer, or personal digital assistant (PDA). The Web browser capabilities of these small devices are limited and vary from device to device. This diversity of browser type is true even on the desktop, as users access Web sites using many different kinds browsers 3.
This diversity of access and browser types can lead to problems and frustrations for some users whose browser won't display the HTML content of a Web site 4. Therefore, if you are a Web implementor, you should try to make your HTML files as universally accessible and available to anyone using any browser at any time using any device. You can do this by using standard versions of HTML and then validating the HTML source that you produce.
Start with Standards
First, begin with good HTML syntax. The authoritative source for information about Hypertext Markup Language is at the World Wide Web Consortium's site at http://www.w3.org/MarkUp. However, making valid HTML can seem confusing. The most current standard for HTML is in flux all the time. However, you can choose and stick to one of the completed and standardized versions of HTML which are available: HTML 4.01, HTML 3.2, or HTML 2.0. These versions give you many features to implement a Web site.
In creating your HTML files, use a software program that gives you the capability to create standard HTML. Many new Web implementors might be surprised to know that HTML can be written easily using only a text editor. While popular software programs exist to generate Web pages, these programs often produce non-standard HTML containing elements and attributes particular to only one brand of Web browser. By sticking with a plain text editor, you can be assured to create only valid HTML.
Create Valid HTML
A good resource for making sure that you produce valid HTML code is the "Viewable With Any Browser Accessible Site Design" guidelines at http://www.anybrowser.org/campaign/abdesign.shtml. These directives are specifically written to address the need for Web pages that are viewable with any browser, not just one brand or type. Making valid HTML also helps users with disabilities. The Bobby service at http://www.cast.org/bobby/ gives you tips and an automated validation service for helping your HTML comply to standards that help people with disabilities. While building HTML files, you might get bogged down in the syntax. A fantastic little software program called Tidy can help you tremendously. Tidy is a free program that you can get at http://www.w3.org/People/Raggett/tidy/. A free Windows GUI Version of HTML Tidy by André Blavier is at http://perso.wanadoo.fr/ablavier/TidyGUI/. With Tidy, you can clean up your HTML files and remedy syntax problems quickly. Tidy will alert you to non-standard problems in your HTML source and give you warnings as well as error messages. Tidy can also "pretty print" your HTML files, allowing you to line up HTML elements on a page with uniform indentation and margins, so that your HTML file is easier to look at and maintain.
You can get a free HTML editor for Windows 95/98/NT/2000 with integrated support for Tidy at http://www.evrsoft.com/. A text and HTML editor for Windows with built-in support for running HTML Tidy is available at http://www.notetab.com/. These tools help you quickly and easily produce HTML that conforms to standards.
Validate HTML Files
Once you've created a complete HTML file and have deployed it on a Web site, you check it using an online validator service. The service offered by the W3C at http://validator.w3.org is a great place to start. This validator service lets you check a page for compliance with W3C standards by just entering your URL and hitting a button. You'll see a list of errors that are in your page. If you use cascading style sheets (CSS), you can check your syntax using the CSS validator, available through a link from this service.
Gain the Benefits
Once you do the work to have valid HTML, you'll increase the chances that anyone using any kind of browser should get useful information from your Web site. You can be assured that your Web pages are well-positioned for future browsers and can be interpreted by old browsers in the best way possible.
- Norton, Patrick. "Cut That Cord, Baby... Wireless Tech at CES," ZDTV, 1/8/2000 http://www.zdnet.com/zdtv/freshgear/products/story/0,3679,2419487,00.html
- Cohen, Adam. "Wireless Summer," Time, 5/29/2000 http://www.time.com/time/magazine/articles/0,3266,45626,00.html
- "BrowserWatch - Stats Station," 6/4/2000 http://browserwatch.internet.com/stats/stats.html
- "Viewable With Any Browser," 6/4/2000 http://www.anybrowser.org/campaign/