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The Development of HTML

HTML is the markup language used to create World Wide Webdocuments. Although official HTML specifications have been indevelopment for some time, individual Web browsers may recognizeproprietary tags that are not includedin the specifications. When most people ask for a list of "all theHTML tags" they generally want to know which tags they caninclude in their pages with reasonable certainty that people viewing thosepages will see what the author wants. The Bare Bones Guide toHTML isdesigned to meet this need. I have attempted to include all of the tagssupported by major browsers today, but there are a number of nuances thatmakethis an inherently imprecise process.

The official standards body for HTML is the World Wide Web Consortium (W3C). The W3C has issued severalversions of the HTML specification, including HTML 2.0, HTML 3.0, HTML 3.2, and most recently HTML 4.0. At the same time, however, browser manufacturers, such as Netscape and Microsoft, have often developed their own "extensions" to HTML outside of the standards process andincorporated them into their browsers. In some cases, such as Netscape's<CENTER> tag, these extensions have become incorporated into the official standard.

HTML2.0, which codified the current state of HTML as of June, 1994, is thebaseline standard that all browsers today -- including text-based browsers --should support. HTML 2.0 reflects the original conception of HTML as adevice-independent markup language for displaying the organization ofinformation, rather than specifying exactly how pages should be displayed. If you want to be sure that all users will be able to view everything on yourpages, use only HTML 2.0 tags.

The HTML 3.0draft, issued in 1995, attempted to build upon HTML 2.0 with theaddition of features such as tables and greater control of text flow aroundgraphics. Although some HTML 3.0 features were widely adopted bybrowser developers, many were not. In some cases, alternativeapproaches implemented by browser developers became more widespreadthan the "official" tags. The HTML 3.0 draft has now expired,and is therefore no longer an official standard.

In January 1997, W3C adopted the HTML 3.2recommendation, which was designed to reflect and standardizegenerally-accepted practices. Therefore, HTML 3.2 includes the HTML3.0 tags that were adopted by browser developers such as Netscape andMicrosoft, as well as widely-supported extensions to HTML.

HTML 4.0, the current standard, became a W3C recommendation in April 1998. This version includes a number of new formatting elements, changes related to scripts and style sheets, and several modifications to make Web pages more accessible to people with disabilities. The current versions ofmajor browsers should support all, or virtually all, these tags.

For the future, W3C is working to refomulate HTML in the context of the extensible markup language (XML), a broader and more flexible standard. For more information, see the current W3C working draft, adopted in December 1998.

There are also some Netscape and Microsoft extensions to HTML thatwere not incorporated into the official HTML standard. By popular request, they are listed in the Bare Bones Guide to HTML. In deciding whether to use any of the tags listed as Netscape or Microsoft extensions, remember that people using other browsers may notsee your pages rendered the way you intend.

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Prologue

The prologue item should go at the very beginning of your file. Theprologue is not required for browsers to recognize an HTML document,although this can provide browsers and people reading your HTML sourcefile with an indication of which tags it includes. The exact syntax of theprologue varies depending on which version of the HTML DTD (documenttype definition) you are using. I've included the prologue to use if yourdocument conforms to HTML 4.0; don't use this if you include Netscape orMicrosoft extensions.

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<XMP>

Earlier version of HTML also included the <XMP> (example) tag, and some people still use it to display un-rendered HTML syntax on a page. However, browsers handle <XMP> inconsistently, and the tag is listed as obsolute in the current HTML specification. The <PRE> tag should be used instead.

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<BLOCKQUOTE>

The suggested rendering of the <BLOCKQUOTE> tag is to indentthe leftand right margins, and this tag is frequently used to achieve indenting(whichHTML 2.0 does not support directly) rather than for quoted material. Beaware that not all browsers display the tag this way, although morebrowsers seem to be indenting it as time goes on.

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Alignment Tags

The HTML 4.0 specification includes both the alignment attributes forparagraph and header tags, and the <CENTER> tag originallydeveloped by Netscape. These days, the main area in which <CENTER> isnecessary is in situations (such as centering a table in Netscape Navigator), where a browser doesn't recognize the alignment attributes.

The biggest problem with <CENTER> is that it impliesa paragraph break around the centered material, but browsers that don'trecognize the <CENTER> tag will simply ignore it, and thus not renderthe document the way the author intended it. As more browsers today recognizethe alignment tags, using <P ALIGN=CENTER></P> willincreasingly be preferable to the nonstandard <CENTER> tag.

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The <P> Tag

Most HTML tags are "containers;" they have a beginningand an ending tag, with text in the middle (e.g. <B>This is inboldface</B>). The <P> tag, by contrast, was originally definedas a standalone tag that marked the space between paragraphs. Theproblemwith this approach is that it didn't allow for features such as centering andright-aligned paragraphs, because there was no way to mark the beginningandend of the text to be aligned. Consequently, the HTML 3.0 proposal fromitsearly days has defined <P> as a container tag, so that paragraphsshouldbe represented as <P>Here's some text</P>, and the opening<P> tag can contain alignment and other attributes. The closing</P> tag can often be left off when you are not setting the alignmentof a paragraph, although using it may make the boundaries of paragraphscleaner in your HTML source file.

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Color Tags

Color values are entered in the form of a hexadecimal triplet specifying red, green, and bluevalues. My WWW Help Page has a section of links to utilities that can generate these codes for you.

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Copyright © 1995-1999 Kevin Werbach.
Last updated February 1, 1999.