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Electronic manuscripts contained control codes or macros for formatting/layout. In other words: content and layout were all mixed up in the same "machine code", **specific to the process that was being performed and to the system that was performing it. These codes and macros tended to be proprietary, leading to issues of exchange, and repeated typesetting costs (e.g. when printers were using different printing presses, or when a press was replaced by a new one from a different manufacturer).
September 1967: a Presentation by William Tunnicliffe from the GCA (Graphic Communications Association) at the Canadian Government Printing Office on "The separation of information content of documents from their format" leads to the start of the generic coding movement (for example, instead of "format-17" use "heading") and a "Generic Coding" project inside the GCA Composition Committee.
Stuff for boring old farts. TL;DR.
In 1969, three guys at IBM conduct a project for integrated law office information systems: Goldfarb, Mosher, and Lowrie. They come up with the Generalized Markup Language (GML), as a means of allowing text editing, formatting, and information retrieval systems to share documents. GML is based on the generic coding ideas, but rather than a tagging scheme it introduces the concept of a formally-defined document type with an explicit nested element structure.
GML was implemented in mainframe industrial-strength publishing systems. (IBM was the second largest publisher in the world!)
In 1978, the ANSI committee on Information Processing starts a project on Computer Languages for the Processing of Text. They ask Goldfarb to lead the project for a text description language based on GML. A first working drft is published in 1980. Draft 6 is issued in 1983 and adopted by the US Internal Revenue Service (IRS) and Department of Defense (DoD).
In 1984, ANSI and ISO team up in ISO/IEC JTC1/SC18/WG8. They issue a draft standard for SGML - Standard Generalized Mark-up Language - in October 1985.
In 1986, the first approved version of SGML is published - using a system developed internally at CERN -as ISO 8879:1986, .
SGML is the basis for the later HTML (an application of SGML, defining a specific vocabulary), and XML (a subset of SGML conventions as well as an extention).
- 1990: Tim Berners-Lee (@CERN) specifies a simple HyperText Mark-up Language and writes browser and server software.
- 1991: He issues the first public description of HTML, comprising 18 elements, strongly inspired on SGMLguid (a CERN Application of SGML).
- 1995: HTML 2.0 is published as RFC 1866 (Request For Comments).
The advent of desktop publishing and WYSIWYG for the masses (sometimes called WYSIWY__D__ - What You See Is What You Deserve - by those "in the know" -- hands up, those who remember the joys of converting publications between Ventura, PageMaker, Interleaf, DECWrite, ...) also led to a proliferating practice of creating web pages that used HTML as a formatting language and in doing so - again - mixed content and formatting instructions.
- more semantics (an SGML for the web, later to be XML)
- a separate way of coding style and layout (CSS, Cascading Style Sheets)
CSS is designed to enable the separation of presentation and content, including layout, colors, and fonts.
This separation can
- improve content accessibility,
- provide more flexibility and control in the specification of presentation characteristics,
- enable multiple web pages to share formatting by specifying the relevant CSS in a separate .css file, and
- reduce complexity and repetition in the structural content.
Separation of formatting and content also makes it feasible to present the same markup page in different styles for different rendering methods, such as on-screen, in print, by voice (via speech-based browser or screen reader), and on Braille-based tactile devices.
- Identical html
- Different images and CSS
- Resulting in radically different visuals!
- https://en.wikipedia.org/wiki/Cascading_Style_Sheets
- https://en.wikipedia.org/wiki/Separation_of_content_and_presentation
And if you have trouble sleeping:
- The SGML Handbook by Charles Goldfarb