HTML: the HyperText Markup Language
Background
- History
- 1989: Web concept invented at CERN
- 1990: first Web prototype
- 1993: 50 known HTTP servers
- 1994: more than 1500 registered HTTP servers
- Service overview
- Powerful hypertext support:
provides a way to access a remote HTML document.
- Processing functions limited:
uses a crude input mechanism that is
inferior to modern word processors in most ways.
HTML's two significant advantages
- Hypertext: easy access to other documents.
Document A can contain a pointer to document B.
Document A can be on the same machine as document B
or on a machine 10,000 km. away.
- Universality.
Handled by millions of computers worldwide: PC, Mac, mainframe, etc.
No other word processing language is so widely recognized.
WYSIWIG versus markup word processing
- WYSIWIG: "What You See Is What You Get"
- Used by most modern word processors, e.g., MSWord.
- Formatting commands are issued and the effect is seen
immediately on the screen.
- The formatting commands themselves are invisible.
- Markup languages
- Standard approach in the 1970s and 1980s
when the hardware was not fast enough to support WYSIWIG.
- Document is edited with a conventional text editor, e.g., vi.
- Formatting commands are embedded in the document as text.
- Separate translation step required to produce formatted output.
- HTML is a markup language; WYSIWIG HTML editors do exist.
HTML syntax
- Markup tags
- Most commands use this syntax:
- Begin formatting: <tag>
- End formatting: </tag>
- Tag names are not case sensitive.
- Usually, newline is treated the same as space.
- Special characters
- &CharacterRepresentation;
- CharacterRepresentation choices include:
lt, gt, amp, quot
- Lots of information about HTML available on the web:
A Yahoo HTML site
A simple HTL document
<html>
<title>Simple example</title>
<h1>First-level heading</h1>
<ul>
<li>List item one.
<li>List item two.
<b>Some bold text under item two.</b>
</ul>
<h3>Third-level heading</h3>
</html>
Anchors for hypertext