Chapter 22 Browsing The World Wide Web

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Chapter 22 - Browsing The World Wide Web

• Introduction
• Description Of Functionality
• Obtain textual information, recorded sounds, or
  graphical images from a variety of sources on
  remote computers as requested.
• Display the retrieved information automatically.
• Store a copy of retrieved information on disk.
• Print a copy of retrieved information on paper.
• Follow a reference found in a document to related
  documents, possibly on different computers.
• Browsing vs. Information Retrieval
• Although they transfer data efficiently,
  information retrieval services such as FTP do not
  display the contents of documents for users.

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Chapter 22 - Browsing The World Wide Web

• A browsing service permits users to view
  information from remote computers without knowing
  the names of files. After obtaining a copy of a
  document from a remote computer, the browsing
  service automatically displays the contents, and
  allows the user to select related documents.
• Early Browsing Services Used MenusGopher
• A menu-driven browsing system displays a menu of
  choices for a user. By selecting an item from the
  menu, the user can request the browsing service
  to retrieve information from a file or retrieve
  another menu.

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Chapter 22 - Browsing The World Wide Web

• A Menu Item Can Point To Another Computer
• A browsing system hides computer boundaries
  completely, and makes information on a a large
  set of computers appear to be part of a single,
  integrated system. A browser can jump from one
  computer to another without a user knowing or
  caring about which computers are being accessed.
• How a Browser Works
• An Example Point-and-Click Interface
• Combining Menu Items With Text

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Chapter 22 - Browsing The World Wide Web

• The Importance of Integrated Menus
• Curent browsing services embed menu items in
  other information, eliminating ambiguities and
  making it easier to understand each item,
  combining menu items with other information
  encourages a user to explore items as they are
  encountered.
• Menus Embedded In Text Are Called Hypertext
• Although documents in a hypertext system can
  contain a complex maze of references, the
  complexity may not be obvious to a user who can
  view only one document at a time.
• Multimedia

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Chapter 22 - Browsing The World Wide Web

• Video And Audio References Can Be Embedded In
  Text
• A hypermedia system can embed references to
  nontextual information as well as references to
  textual information in a document.
• If the user selects a reference to a document,
  the hypermedia system displays the document if
  the user selects a nontextual reference, the
  hypermedia system plays the audio or displays the
  images.
• The World Wide Web
• In addition to containing textual information,
  World Wide Web documents can contain sounds and
  graphical images. To display nontextual
  information, a computer must have multimedia
  hardware

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Chapter 22 - Browsing The World Wide Web

• Browser Software Used To Access The Web
• A Web browser consists of a program that provides
  access to hypermedia documents on the World Wide
  Web. A Web browser displays a given document, and
  allows the user to select among highlighted
  items, which can consist of either text,
  graphics, or sound.
• An Example Hypermedia Display
• Control Of The Browser
• External References
• Recording The Location Of Information
• A Uniform Resource Locator consists of a short
  character string that identifies a particular
  multimedia document. Given a valid URL, a browser
  can go directly to the page without passing
  through other documents.

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Chapter 22 - Browsing The World Wide Web

• Bookmarks
• How The World Wide Web Works
• A URL Tells A Browser Which Computer To Contact
• A URL Tells A Browser Which Server To Contact
• Each URL uniquely identifies a page of
  information by giving the name of a remote
  computer, a server on that computer, and a
  specific page of information available from the
  server.
• Use Of The Name WWW In URLs
• A Browser Provides Access To Multiple Services

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Chapter 22 - Browsing The World Wide Web

• Inside A Browser Program
• A browser's novelty and power arise becasue it
  integrates access to multiple Internet services
  into a single, seamless browsing system. The
  browser uses information in the URL to
  automatically select an access mechanism from
  among such services as remote login, file
  transfer, and gopher.
• Getting Started With A Browser
• Summary
• An Observation About Hypermedia Browsing

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Chapter 22 - Browsing The World Wide Web

• Terms
• bookmark
• browser
• browsing
• hypermedia
• hypertext
• information browsing service
• menu
• point-and-click interface
• selectable item
• Uniform Resource Locator (URL)
• World Wide Web (WWW)