It's hard to understand how HTML5 arrived on the scene without understanding the complete history of HTML. While most people associate the beginnings of HTML with the early 90s, the story actually starts a full decade before that.
1980: ENQUIRE
The concept of HTML was invented at CERN, the European Laboratory for Particle Physics in Geneva, Switzerland, and future home of the Large Hadron Collider. Tim Berners-Lee, working as an independent contractor in the computing services division of CERN, created a primitive hypertext system called ENQUIRE, written in the PASCAL programming language.
The concept of hypertext had been around since the 1940s in theory, and ENQUIRE was a primitive implementation, closer to a wiki than a modern web browser. The name was borrowed from the book " Enquire Within Upon Everything, " an encyclopedic how-to book for first published in 1856. Having completed this project, Berners-Lee left CERN the same year to work in private industry.
1989-90: HTML, WorldWideWeb
It wasn't until 1989 when Berners-Lee, who had rejoined the organization, saw the opportunity to combine his concept with the internet. CERN was already a major internet hub, but Berners-Lee's key innovation was that researchers would be able to link directly from one document to another using " hypertext. " Therefore, the linked documents could be presented as a " web " of information that would be more easily searchable and understandable.
The next year, Berners-Lee, with the help of Robert Cailliau, built the first web browser and editor - dubbed WorldWideWeb - and created the HTTP protocol to deliver web content. HTTP used a new text format - HTML (HyperText Mark-up Language), which was basically heavily on SGML (Standard Generalized Mark-up Language), an internationally accepted method for structuring documents. The earliest surviving HTML document was put online that year, and can be viewed here. http://www.w3.org/History/19921103-hypertext/hypertext/WWW/Link.html
Many HTML elements, such as the TITLE tag, the headers tags, and P tags, were taken directly from SGML. The main innovation was the A tag with an HREF element, allowing pages to be linked together.
1991-92: HTML Tags
In 1991, HTML Tags, an informal CERN document listing 22 HTML tags, was created. Researchers and computer scientists around the world began to take an interest in what Berners-Lee and CERN were doing, and the WWW-talk mailing list was started.
HTML caught the attention of researchers at the National Center for Supercomputer Applications (NCSA), including programmer Marc Andreessen, who would go on to found Netscape. The NCSA team began work on a browser of their own dubbed Mosaic. In December 1992, Andreessen appeared on the WWW-talk mailing list and proposed his implementation of a tag for images, the IMG tag.
1993: Hypertext Markup Language, HTML+
As the efforts progressed, the official Internet standards group, the IETF (Internet Engineering Task Force), tried to arrive at a concrete proposal for HTML. In 1993, a proposal entitled “Hypertext Markup Language” was published by the IETF as a draft. Another draft, HTML+, was also published by the IETF as a competing proposal later that year.
In March, 1993, Lou Monteulli released the Lynx text-based web browser. Lynx was designed for terminals and for computers that used DOS without Windows. Then in April, the Mosaic browser was released, added images, nested lists and forms.
1994: W3C
1994 was a “big year” for HTML. In May, the first World Wide Web Conference was held in Geneva, drawing a grand total of 380 mostly European attendees, mainly from the academic and scientific communities. In July, the specification for HTML 2.0 was proposed, essentially a collection of all the HTML tags that had been implemented by various independently developed browsers.
In November, Marc Andreessen left NCSA for Silicon Valley where he met Jim Clark. He and Clark formed Netscape Communications, with plans to create and market their own browser. Netscape would go on to become the first mass market browser.
Partly in response to what some saw as the increasing ability of private companies to drive the development of HTML, the World Wide Web Consortium was formed to oversee the development of open standards in late 1994.
1995: HTML 2.0, HTML 3.0 Draft
In 1995, HTML 2.0 was officially published. Meanwhile, developer Dave Raggett, who had been working for a while on new ideas for streamlining and extending HTML, published a draft version of HTML 3.0. Raggett’s proposal included many of the ideas that would be incorporated into modern HTML, including the first support for style sheets and tables, along with other that would be destined for the cutting room floor (such as a replacement for the IMG tag called FIG).
Unfortunately, chaos reigned as the standards organizations were unable to quickly come to an agreement on all of Raggett’s proposals. In response, different browsers all implemented the ideas of “HTML 3” in different ways. Upping the stakes, Microsoft introduced Internet Explorer later in the year to compete with Netscape.
1996: ERB
In February of 1996, the WWWC created a new group, the HTML Editorial Review Board, to help try to standardize the chaotic development of HTML. Consisting of members from the major technology companies, ERB held meetings to try to reach consensus on tags and features. This led to some amusing negotiation – at one point, Netscape agreed to deprecate the BLINK tag if Microsoft would remove the MARQUE tag from IE. One key development to come out of the ERB meetings was the OBJECT tag, which would become part of the HTML standard the following year. Later that year, the ERB morphed into the HTML working group which would begin development of the next version of HTML – code-named “Cougar” – HTML 4.
1997: HTML 3.2, HTML 4.0
By January 1997, the W3 Consortium finally was ready to officially move on from HTML 2. Called HTML 3.2, the new version finally codified the disparate ideas that had been bouncing around in different forms, and included tables and Java applets.
Meanwhile, work on HTML 4 continued. In December, HTML 4.0 was published as a W3C Recommendation, finally bringing us features such as CSS and scripting
1999: HTML 4.01
In December 1999, the version of HTML that would reign supreme for the next decade or so, HTML 4.01, was published. It offered three implementations to ensure backwards compatibility: Strict – in which deprecated elements were forbidden, .tutorialsitional – in which they are allowed, and Frameset – in which mostly frame-related elements were allowed.
2000: XHTML 1.0 Published
Around this time, there was widespread sentiment that the future of HTML lay in better automated parsing. This could be achieved by adherence to the stricter subset of SGML, XML, which demanded the use of well-formed tags. XHTML, a reformulation of HTML 4.01 using XML, was published in January, 2000.
2001: XHTML 1.1 Published
In May, 2001, XHTML 1.1, which was aimed at the modularization of XHTML, was released.
2002: XHTML 2.0 Working Draft
Between 2002 and 2006, the W3C would release 8 working drafts of XHTML 2.0. XHTML 2.0, which was designed not to be backwards compatible with XHTML 1 or HTML 4, caused some controversy in the developer community. The standard is still in development as of 2009.
2004-2007: WHATWG
In June 2004, two days after a proposal by Opera and Mozilla was voted down by the W3C, a new group formed by representatives of Mozilla, Apple and Opera, the Web Hypertext Application Technology Working Group, or WHATWG, was formed in order to create a platform for web applications. Google later became involved in the group; Microsoft was invited but did not join. WHATWG’s goal was to move the HTML standard forward in the face of what they saw as slow movement by the W3C. Part of the critique of the W3C process was that the focus on XHTML 2.0 was too document-centric, and not suitable for commercial applications.
In 2006, Tim Berners-Lee published a blog post entitled “Reinventing HTML” http://dig.csail.mit.edu/breadcrumbs/node/166 :
Some things are clearer with hindsight of several years. It is necessary to evolve HTML incrementally. The attempt to get the world to switch to XML, including quotes around attribute values and slashes in empty tags and namespaces all at once didn't work. The large HTML-generating public did not move, largely because the browsers didn't complain. Some large communities did shift and are enjoying the fruits of well-formed systems, but not all. It is important to maintain HTML incrementally, as well as continuing a .tutorialsition to well-formed world, and developing more power in that world. The plan is to charter a completely new HTML group. Unlike the previous one, this one will be chartered to do incremental improvements to HTML, as also in parallel xHTML. It will have a different chair and staff contact. It will work on HTML and xHTML together. We have strong support for this group, from many people we have talked to, including browser makers.
In April 2007, Mozilla, Opera and Apple jointly requested that the W3C adopt the work of the WHATWG under the name of HTML 5.
2008: HTML 5.0
In January, 2008, HTML 5 was published as a Working Draft by the W3C.