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Contents
Guide to good practices for WWW authors
HTML is an evolving standard and enhancements and additions are continually being developed. Decisions about the standard are arrived at by consensus within the HTML Working Group of the Internet Engineering Task Force (IETF), an open forum to which anyone in the Internet community may contribute. The process involves discussion, preparation of draft standards, revision and refinement, and final publication as an RFC (Request for Comments). As each new version is finalised and published, the developers of browser and server software begin to incorporate the standard into their software. Documents whose HTML conforms to the current standard will therefore have maximum readability across all platforms.
Unfortunately, this process is slow and unwieldy, as democratic processes often are. Software developers are keen to gain a competitive edge by pushing forward with new HTML extensions, and Web authors wanting to extend the graphical possibilities of their Web pages sometimes attempt to make HTML structural elements perform layout functions for which they were never intended. The result is that we have some proprietary extensions to HTML which can be viewed with only one browser, and HTML tags pushed to create effects which give unpredictable results on different platforms. Either scene should be strenuously avoided by HTML authors who are serious about conveying information on a wide scale. Where the effort invested in producing Web documents must reap lasting benefits, there can be no argument. Standard HTML reaches further and remains usable as browser software evolves and new tools become available. Authors optimise the use of their information for both present and future by using standard HTML.
For maximum portability and usability, use standard HTML.
Conforming with the standard means using the elements included in the most recently ratified version of HTML and using them appropriately. The current standard is HTML 2.0, issued as RFC 1866. This standard should now be incorporated into all the most recent versions of Web browsers. The WWW Consortium site maintains information on current standards and discussions, and extensive information on WWW and HTML.
There is however, a little more to producing versatile usable documents than writing them with the HTML standard in front of you. With manual markup, it is relatively easy to make an error in HTML.
One way to ensure that your HTML is valid is to use a validation service such as WebTech's HTML Validation Service (A HREF="http://www.hensa.ac.uk/html-val-svc/">mirror site at HENSA).
Alternatively you can download validation software to a local machine, e.g. WebLint or HTMLCHEK, and run it on your documents. These methods will point out semantic errors in HTML and possibly even correct them.
Validate your HTML markup.
As well as running your documents through an automatic validation process, it is good practice to test their practical usability on a number of browsers, and especially, to view them with a plain text browser such as Lynx. Lynx should be available on a central Unix machine at each campus. If it is not, see your System Manager about having it installed. Such trial viewing does not imply that only the tags viewable with a plain text browser should be used; rather that the documents should be usable and make sense with plain text browsers as well as graphical browsers.
Make sure your documents are usable on a range of browsers.
Usability in this context means not just valid HTML, but providing alternatives to images, limiting the size of the document, possibly providing alternative plain text routes through your body of information if navigation is strongly graphically based.
The use of browser-specific extensions to HTML such as Netscape extensions is not recommended, particularly for documents intended for the general public. On browsers other than the one for which you've written your HTML, there may be unpredictable or even awful results, and in the final analysis, such practices erode the principle of universal, cross-platform access which is what the WWW is all about. While it may be argued that your browser-specific documents can be optimally viewed by 70 or 80% of Web users now, it's salutary to remember that in using standard HTML, documents are viewable by 100% of Web users both now and in the future. Developers of proprietary extensions provide their own extensions in addition to standard HTML.
Don't use non-standard extensions in documents intended for general readership.
Conformance with the accepted standard (HTML 2.0) is by far the most desirable practice, but the reality is that the use of browser-specific tags and tags undergoing definition is not uncommon. A number of elements proposed in HTML Version 3.0 are already being supported by various browsers and many authors have begun using them. The TABLE tag, for instance, which has been worked on by standards makers for some time, represents a significant advance in the layout possibilities for HTML documents. Other tags coming along in HTML 3.0 enable alignment of headings, limited control over font size, specification of image dimensions, alignment of text, and the insertion of background patterns in documents.
WWW authors using tags which are not included in the current standard need to see their own document provision in the wider context and to think about the portability and usability of their documents by the range of users. There are measures which may help to mitigate the fragmenting effects of using non-standard HTML:
Another measure is to make apparent the variety of HTML being used. A number of different versions of HTML can be identified in the Doctype declaration at the beginning of the document. Further information can be found in the list of HTML public identifiers.
Here is an example of a very specific type being declared (taken from the home page of Chris Lilley, of Manchester University's Computer Graphics Unit):
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 1996-01//EN">
<html>
<head>
<title>Chris Lilley</title>
<link rev="made" href="mailto:c.c.lilley@mcc.ac.uk">
</head>
Use the Doctype declaration to declare the type of HTML used.
Provide alternative options to non-standard elements.
Graphics Multimedia Virtual Environments Visualisation Contents