HTML standards

Lecture Notes – HTML Standards – Prepared by Sukh Sandhu

Page | 1 Concepts

Why We Need Standards

The World Wide Web, invented in the early 1990's, made it possible to
distribute documents globally without worrying about what kind of computer
or software the user had (as long as the user had an Internet-connected
computer and a Web browser, of course). The way the Web was defined, the
syntax of HTML was independent of computer type, and each kind of Web
browser created was meant to display an HTML file correctly.

At least this was the dream.

The reality is that during the 1990's, economic and cultural forces muddied
the waters. Some people made Web browsers that recognized HTML
elements that had not been accepted as standards. Some companies created
Web browsers fashioned to recognize company-specific (proprietary) HTML
elements and attributes of elements. Some companies created Web browsers
that recognized proprietary elements and attributes that were in conflict with
the proprietary elements and attributes of other companies.

Without standards, the World Web Web becomes fragmented. When you have
to worry about what kind of browser you are using in order to see Web
content, you're experiencing a problem that the Web was originally invented
to solve.

We need standards to make sure that all Web content is viewable by many
different kinds of Web browsers--and not just the Web browsers of today,
but the handheld devices, cell phones, or other Net devices that may be
invented in the future.

Using standards also lowers HTML production and maintenance costs. By
educating HTML implementors in a fixed set of standards, you can reduce
training time, increase the accuracy of implementation, reduce display

errors, improve the appearance of Web pages, and make it possible for
further maintenance with the least amount of hassle.

I advise that you stick to HTML standards and validate your HTML files so
Page | 2 that your Web pages are most likely to be satisfactorily displayed in the
widest range of browsers and devices. The organization that coordinates
HTML standards is the World Wide Web Consortium (W3C). You should
bookmark their site as the best and most authoritative source for HTML
standards. See also the Web Standards Project.

Key things to keep in mind:

1. HTML standards help you reach the widest possible audience.
2. HTML is now specified as XHTML 1.0 (HTML + XML = XHTML). The
expressiveness of XHTML 1.0 is quite impressive and complex.
However, "plain old" HTML is still usable and quite useful.
3. There are many technologies that are associated with HTML because
they are used on a Web page or in conjunction with HTML. But these
technologies are not HTML:
o CGI (Common Gateway Interface)
o Java
o JavaScript (JavaScript is also not Java)
o Dynamic HTML (DHTML)
o XML (Extensible Markup Language)
o A variety of other emerging technologies.
4. Sometimes you are going to have to break the rules and use non-
standard syntax for good reasons. Try to keep this to a minimum.

How to Follow HTML Standards

1. Identify which version of HTML you are using in your document
through the DOCTYPE line at the top of your file. For documents that
use only HTML 2.0 features (like hello, world), you could use this
DOCTYPE statement:
<!DOCTYPE html PUBLIC "-//IETF//DTD HTML 2.0//EN">

For documents that use HTML 3.2 features, you could use this
DOCTYPE statement:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">

There are other DOCTYPE statements that you will need to use for
other versions of HTML. For example, to use HTML 4.01 features and
Page | 3 a "loose" conformance to syntax standards, you could use this
DOCTYPE statement:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01
Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

You use another DOCTYPE statement when you create an XHTML
document. For example, look at this simple XHTML document and
use your browser to view its source to see its DOCTYPE statement.

See the W3C site for more information on document types and
DOCTYPE statements.

The important thing to remember is that a DOCTYPE statement is
essential to assisting validation software in checking your document.

2. Use tools that support standards. In particular, install and use the Tidy
program or Tidy GUI on your computer.
3. Use validation to check the syntax of documents you create.
4. Refer to W3C for technical and syntax information.

Having correct HTML syntax helps your Web site's usability in the widest
range of browsers. However, don't become a "syntax snob"--one who
proudly verifies and tweaks HTML pages to perfect syntax, yet ignores the
meaning and content of those pages.

Consider these HTML tips when you are making Web pages.

Exercise: Check a Web document

Use validation to check the syntax of documents you have created.

Validating a Web Document

You can detect and diagnose HTML syntax errors in your document by using
a validator. First, make sure you have an appropriate DOCTYPE statement
Page | 4 (and, optionally, a character encoding statement) in your document. Then:

1. Go the the Web page http://www.htmlhelp.com/tools/validator/
2. Enter the URL of your assignment in the box which is labeled URL:
3. Make sure that the checkbox for "show input" (second checkbox
below the URL: box) is checked
4. Click on "Validate it!"
5. Fix the syntax errors you have. A good idea is to start with the first
error that you have, fix it, and then re-validate. Repeat until you have
no syntax errors.
6. If you want, you can use the Tidy service to help you. See The HTML
Toolbox under "Utilities." Tidy can help you diagnose HTML syntax
errors, but it is not a validator. Any output you get from Tidy should
be run through the validator again

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