Did you ever stop and wonder what the Web might look like if there were no standards? I think it would be a web of confusion.

It reminds me of a file cabinet that I have full of important electronic data that I've accumulated over the years. I have accounting information on floppy disks from years ago. The data was written in what is now long-obsolete software in file formats I can't access. If the World Wide Web were like my file cabinet it would be full of information written in Word 97 and WordPerfect and, depending on the year I generated the files, some of it would be in the Apple Macintosh format while others would be in Microsoft PC format. I have images created in formats ranging from TIFF to PCX. The files I've generated over 10 years ago are almost all in proprietary formats.

What a limited and expensive World Wide Web it would be if there were no standards.

Fortunately for us the World Wide Web's creator Tim Berners-Lee not only created a protocol for retrieving documents, the HyperText Transfer Protocol (HTTP) he also created a standard language for creating documents to be retrieved called the HyperText Markup Language (HTML).

Those of us who've traveled the Internet since it started will recall how quickly it became proprietary in its structure and abilities. Prior to the so-called browser wars, the World Wide Web was fragmenting into competing languages, overlapping functionality, and proprietary code that made any attempt at universal Web design a frustrating experience. Many of us have felt the frustration of trying to write Cascading Style Sheets that displayed our designs in an identical, if not similar, fashion across multiple Web browsers and platforms. Besides presentation problems, we also experienced functionality issues with JavaScript (from Netscape) versus JScript (from Microsoft). The browser wars between Netscape Navigator and Internet Explorer really brought the issue to the forefront as the two competed to provide a richer, more dynamic experience for providers and end-users alike.

The subsequent creation of the World Wide Web Consortium and its recommendations (read standards) has done much to alleviate the problems caused by the browser wars. The browser makers themselves have also contributed to the solution by upgrading their browsers to render HTML code more consistently. So we've seen a return to the original plan - a Web document based on a standards-based language.

While Web designers today understand the need to write code that works in all browsers and on all platforms, many simply don't appreciate the consequences of non-standard code. Today's Web browsers ask much from the humble HTML document. The Web page has become a starting-off point for information. Eventually the Web page content is used to formulate printed pieces, populate forms including PDF pages, and some Web pages are components of an advanced Web application or software that runs via the Internet. Not all Web pages can fulfill these purposes. To use a Web page to create a PDF, or populate a back-end database, or feed a Flash application, the content must be consistent; it must be standard. The standard that promises the most possibilities is XHTML. Other standards that help multi-purpose your content include Cascading Style Sheets, XSL-T, and XML.

The purpose of this article is to demonstrate how Dreamweaver MX 2004 can help you write standards-compliant code. You'll learn how to ensure your documents are written in XHTML, or if you prefer HTML 4.0, etc. You'll learn how to build accessibility into your documents that will help PDAs and cell phones render your Web pages as well as desktop browsers and printers. By writing XHTML-compliant code and using an external stylesheet you'll be able to exploit all of the multi-purposing possibilities available.

What Type of Document Should You Write?
If you want to repurpose the data in your Web page, the most flexible format is XHTML. When your document is written in XHTML that means it's an XML application - in other words, pure data that can be rendered for any purpose. For example, using the XML stylesheet language called XSLT, you can transform XHTML Web pages into any other format including any of the new Microsoft Office Markup languages like WordprocessingML for Word and SpreadsheetMLfor Excel. You can also transform the XHTML into an XML file suitable for importing into many applications including Flash to create dynamic Flash applications and Adobe InDesign to create printed pieces. The possibilities are becoming endless as more applications become XML-compatible.

On the other hand, if you're reworking older Web pages that need to be viewed in early (pre-standards-based browsers) you may want to ensure that they are written according to the rules of HTML in use at the time of the browser release (HTML 4.0, for example).

The solution in both cases is to declare a document type at the beginning of your Web page that announces to the Web browser what version of HTML you're writing. In the "New Document" dialog box, Dreamweaver offers an opportunity to ensure that you create XHTML. See Figure 1, which shows the "Make document XHTML-compliant" checkbox. If you don't check this box, then Dreamweaver will write the Web page in HTML 4.01 Transitional, which means that the document may use deprecated presentational elements such as the font tag. This makes the document backwards-compatible for older Web browsers. When creating a document that's not XHTML-compliant, Dreamweaver generates the following code:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>

<body>
</body>
</html>

Enabling the "Make document XHTML-compliant" checkbox would result in the DOCTYPE shown in the following code:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

Once you've written your Web page as XHTML, you can validate it in Dreamweaver to make sure you've not broken any of the rules of the XHTML language. If you want to exploit the XML capabilities of XHTML, your code has to be valid. To validate your code using Dreamweaver:

1. Open the Web page you've written in XHTML
2. From the Window Menu, choose "Results" or hit F7 to bring up the "Results Panel"
3. Click the Validation tab at the top of the Results Panel
4. Click the green arrow on the left of the Results Panel and choose "Validate Current Document." Note that you can also validate an entire site, or selected files from the site. If the site contains no errors, the results panel will display as shown in Figure 2.