Markup languages are designed for the processing, definition and presentation of text. The language specifies code for formatting, both the layout and style, within a text file. The code used to specify the formatting are called tags. HTMLis a an example of a widely known and used markup language.
A markup language is a type of language used to annotate text and embed tags in accurately styled electronic documents, irrespective of computer platform, operating system, application or program.
The term markup language is derived from the marking up of manuscripts, where handwritten markups were annotated in the form of printer instructions. Markup languages are also used in playlists, vector graphics, Web services and user interfaces. HTML is the most widely used markup language.
There are three types of electronic markup language:
Presentation Markup: Used by traditional word processing systems with WYSIWYG; it is hidden from human users.
Procedural Markup: Integrated with text to provide text processing instructions to programs. Such text is visibly manipulated by the author. Procedural markup systems include programming constructs, where macros or subroutines are defined and invoked by name.
Descriptive Markup: Used to label parts of a document as to how they should be treated. For example, the HTML tag is used to label citations in text.
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Most of us have used a markup language at one time or another. Think about it, have you written a short note or underlined a specific word for emphasis? Have you ever written an entire word in capital letters or used italic letters to emphasize a phrase? Have you used a highlighter in your textbook to isolate a fact?
If you've done any of these, then you've used a markup language. In the context of computerized communications, a markup language is considered a type of communicative language used to separate, annotate, emphasize or otherwise distinguish text on a page from other displayed text. The figure below illustrates an example of markup tags used in HTML 2.0.
Example of HTML 2.0 tag usage
HTML tag example screen.
Web page developers/designers use modern markup languages, such as Hypertext Markup Language (HTML), Extensible Markup Language (XML) and Extensible Hypertext Markup Language (XHTML), to generate the pages shared on the Internet today. HTML, XML and XHTML use markup tags to isolate and change the appearance of selected text.
Markup tags are enclosed within a < and >. The < > symbols are commonly referred to as open and close wickets, respectively. Any characters enclosed within the wickets are considered components of the markup language and will impact the display characteristics of all alphanumeric characters enclosed within the wickets. In the example below
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and are called tags. In this example the word HTML is displayed using bold text.
<p>
this is a paragraph of text written in HTML
</p>
The markup tags in the above example equate to, and act as, instructions for displaying or printing the contents of a web page. When applied to a web page, these instructions are interpreted by a browser executing the display instructions line by line.
