HTML

HYPERTEXT MARKUP
LANGUAGE (HTML)

HyperText Markup Language
(HTML)
 HTML is used to create web documents including
text, images, formatting, and hyperlinks to other
documents.
 HTML documents consists of text and ‘markup’
tags which are used to define the structure,
appearance, and function of the information.
 There are two types of markup tags:
• Container tags – Define a section of text using a
start tag and an end tag. For example, text placed
inside of these tags would appear in bold:
<B>Hello</B>
• Empty tags – represent a single occurrence of an
instruction. For example, the <BR> or break tag is
used to indicate that you want to include a single
space following the text.

Text Authoring Tools
 Any text editor can be used to
create HTML documents.
 The most commonly used text
editors are:
• Notepad (Windows)
• WordPad (Windows)
• Simpletext (Macintosh)

WYSIWYG Authoring Tools
 What You See is What You Get
(WYSIWYG) authoring tools provide
graphical user interfaces to simplify the
creation of HTML documents.
 Examples of WYSIWYG authoring tools
are:
• FrontPage by Microsoft
• Dreamweaver by Macromedia
• PageMill by Adobe
• Netscape Composer

Structure of an HTML
Document
 An HTML document is divided into
two main sections:
• Heading - The HEADing contains information
describing the document, such as its title. The
heading section is indicated by the <HEAD> and
</HEAD> tags.
• Body - The BODY section is where the Web
document text, graphics, and other elements are
placed. The body section is indicated by the
<BODY> and </BODY> tags.

Example of an HTML
Document
<HTML>
<HEAD>
<TITLE>Career and Technical Education
Home Page</TITLE>
</HEAD>
<BODY>This is the part of the Web page
that viewers would see!</BODY>
</HTML>

Graphic Files
• HTML supports two main graphic file formats:
—GIF - Graphics Interchange Format (CompuServe,
pronounced GIF/JIF)
—GIF files provide a maximum of 8-bit (256 colors), use
indexed color, can be interlaced (image displayed in four
passes), and support transparency and animation. GIF
files should be used for images such as logos, cartoons,
and icons.
—JPG – Joint Photographic Expert Group (A jpg encoded
graphics file - pronounced JAY-PEG)
— JPG files provide a maximum of 24 bit color (true color),
can handle grayscale images, allow you to control
compression, and are progressive (a designer can specify
the number of passes to use when displaying the image
(like GIF interfacing). JPG files should be used for
photographs and paintings.

Graphic Files
• A newer format was introduced in 1995--
PNG – Portable Network Format.
– PNG is an open standard.
—Use has been restricted because of limited browser
support. It is generally supported by version 4.0
browsers and above.
—Provides 48 bit color, a compression system,
interlacing (7 passes), and support for 8-bit
transparency

Multimedia File Formats
 Multimedia files are used to provide audio and
video.
 Audio and video may be supplied in two ways:
• Streaming
• Non-Streaming
 Non-streaming files must be downloaded in their
entirety to the hard disk drive of the user’s
machine before playing can begin.
 Streaming technology was developed to
overcome the issue of download time.

Multimedia File Formats
 AVI – Audio-Video Interleaved (A standard format for
computers)
 MOV – QuickTime Video (Format developed by Apple
Computer that displays video, audio, and animation on
Mac and Windows)
 MIDI – Musical Instrument Digital Interface (Audio format
used for synthesized music rather than recordings. Files
are smaller than WAV files
 MPG/MP3 – MPEG (Moving Picture Experts Group) – High
quality compressed format for audio and video
 WAV – Used for high quality recordings for both mono and
stereo audio tracks. Creates relatively large files.

Plug-Ins and Multimedia
Extensions
 Browsers can be extended using
additional software known as plug-ins.
Plug-ins work as part of the browser.
 Plug-ins are available for audio and for
displaying special effect images.
Examples include:
• Shockwave
• Flash
• RealPlayer
• QTVR (Quick Time)

Extensions
 Shockwave by Macromedia
• Used to provide interactive multimedia, graphics,
animations, and streaming audio on the Web.
Applications include games, business presentations
and advertisements. Files containing sound and
video are very large.
 Flash Player by Macromedia
• Provides support for animations, interactive images
and presentations, all with integrated audio clips and
streaming technology. Its main benefit is the small
file size, which is achieved using vector-based
graphics instead of bitmaps. Vector graphics are
scalable, high quality, and interactive.

Extensions
 RealPlayer by RealNetworks
• Provides live and on-demand streamed audio and
video content on the web. It is widely used and is
optimized for slow connections. RealPlayer can
provide various audio qualities up to CD quality
using ISDN and faster connections. Minimum
support for reasonable quality is 28.8 Kbps.
 QuickTime Viewer from Apple
• Supports the viewing of graphics, audio, and video.
NetScape Navigator 3+ and Internet Explorer 3+
are shipped with Quick viewer as part of the
application. Quick time movies are popular because
of their small file size.

Extensible Markup Language
(XML)
 XML is the universal language for data
formatting on the Web. The limited
capabilities of HTML mean that many data
types cannot be presented in a consistent
and sophisticated manner, while XML can
be customized by developers for any
particular task such as:
—Financial data
—Scientific data
—Legal information

Virtual Reality Modeling
Language (VRML)
 VRML is used to create three dimensional
objects with different colors and textures
which can be placed in a virtual reality
space through which the user can move.
 Like HTML, the VRML language is
interpreted by the browser. VRML
supports Java and JavaScript as well as
sound and animation.

HTML

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