Hyper Text Markup Language (HTML)

As the Internet began to take shape, it was essential that there be a common format for all web sites to follow in order to make sure that any operating system could read any web site. Using SGML as a template, the Hypertext Markup Language was developed, with the first specifications being released in the summer of 1991. Unlike SGML, HTML is a fixed programming language, which means that it has a clearly defined instruction set, in the form of HTML Tags, that all HTML documents must follow, although there have been several revisions to this language that will be discussed below.

Although it has matured over the years to incorporate image manipulation and allow integration with other technologies, HTML was originally intended only to handle the formatting of text, as can be seen in the long version of its name. The term Hyper, as applied to HTML means that an HTML document can be coded to allow the reader to access other HTML documents through the use of Hyperlinks. The term Markup, as applied to HTML, refers to the formatting of the text in an HTML document. Both of these terms offer us the key to understanding HTML. At its heart, HTML was designed to allow the developer to control how text will be displayed as well as to allow the user to access related documents via hyperlinks. This is important when understanding the limitations to HTML. Dozens of technologies have been developed to fill the void where HTML cannot go, simply because it was never intended to do more than format text in a platform independent manor. Only now, with the web becoming splintered because of platform dependent or browser dependent technologies such as ActiveX and JavaScript (Both will be discussed in a succeeding section of this module) is HTML broadening its horizons to encompass more than text.

If your ever curious to see an example of HTML, all you have to do is open a web site in Internet Explorer, go to the View menu and select Source. This will bring up a Notepad window that will list the HTML source tags for the active web page. To see how HTML has matured over the years, the following is a brief explanation of the different revisions of HTML.

HTML 1.0

As can be noted from its version number, this was the earliest form of HTML. Designed in October/December of 1990, in its original form, only the NeXT operating system could decode HTML documents. However, its inventor, Tim Berners-Lee noticed the lack of a suitable cross-platform text language for use on the Internet, so in the Summer of 1991 the specifications for his new language were posted on the Internet. Before the publication Berners-Lee revised the code in order to make the language platform independent through the use of an HTML compiling program that has become known as a Browser. Over the next couple of months, several first generation web browsers began to support this language. However, few of these browsers defined the language in the same way, which resulted in a fracturing of the language into dozens of variants, few of which were compatible with one another. For years several standards groups tried to solidify the language and release an Industry Standard for the language, all to no avail until HTML 2.0 was developed. As a result, it is nearly impossible to clearly describe this version since there were so many different variants.

HTML +

In 1993, while the fighting raged to standardize HTML, a proposal was made for a superset version of HTML called HTML +. Unfortunately, the version was never ratified, even though it would have provided for more flexibility than HTML 2.0, which eventually succeeded it. However, it is important to note this version since it impacted the development of later versions of HTML.

HTML 2.0

This was the first revision of HTML to actually be solidified into a Standard, which was released in September 1995. It had taken over four years and several failed attempts to finally solidify the language, but at last it was done. Soon after HTML 2.0 was released to the public, two browsers made their first large-scale appearances, Netscape’s Navigator 2.0 and Microsoft’s Internet Explorer 2.0. Both browsers fully supported HTML 2.0, which was also the first version of HTML to support in-line images and fill-out forms. It is important to note that this was the version of HTML used during the first population explosion on the Internet, when thousands of business and organizations discovered the potential benefits from hosting their own web sites.

HTML 3.0

Soon after the population explosion on the Internet, which brought about the first widespread use of HTML 2.0, developers began to notice shortcomings in the flexibility of HTML. As a result, they began development of a successor for HTML 2.0. Much of HTML 3.0 came from the failed HTML +, which included such parameters as support for tables, text flow around images and complex numbers in addition to more flexibility in page alignments and additional tags for text formatting. However, HTML 3.0 ended up failing just as its successor HTML +, because the changes between HTML 2.0 and 3.0 were so many that upgrading the currently deployed browsers to support this new standard was considered to be not cost effective. Fortunately, like HTML +, many of the attributes for HTML 3.0 would be raised from the dead by the next successful HTML standard, HTML 3.2.

HTML 3.2

Even though it had been less than a year since HTML 2.0 had been published, its time had already run out. In order to bypass the limitations inherit in the version, several browsers began to support proprietary tags to enhance the flexibility of the language. Unfortunately, this only proved to defeat the main purpose of the language, to provide a universal language for the publishing of documents on the Internet. As a result, the W3C organized a committee to develop the next revision of the language. HTML 3.2 was the result, an amalgam of HTML 2.0 and HTML 3.0 as well as some of the proprietary tags, which was finally published in May of 1996. At the time of the publishing of HTML 3.2, several features in common use by the major browsers of the time were noticeably missing. These features included style sheets, frames, scripting, advanced mathematics functions as well as Internationalization. However, HTML 3.2 was eventually fully supported by all major browsers. Netscape Navigator 3.0 and Microsoft’s Internet Explorer 3.0 both fully support HTML 3.2.

HTML 4.0

HTML 4.0, which finally became a standard on December 18, 1997, is only partially supported in Netscape’s Communicator 4.0 and Microsoft’s Internet Explorer 4.0. Previous versions of HTML were developed to match the capabilities of the browsers currently deployed on the market. This has changed in HTML 4.0, which is the first attempt to really expand the functionality of the language by adding support for OBJECT tags, as well as support for Cascading Style Sheets, in addition to supporting most of the features that were noticeably missing in HTML 3.2. The OBJECT tag is notable because it enables scripts, code from scripting languages, to be embedded directly in the HTML source code for a site. Between the OBJECT tag and Cascading Style Sheets, the possibilities for the coding of a web site will be limited only to the imagination of the site developer. The down side of these new features is that they may require major modifications to the architecture of current browsers in order to fully support them.