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Basic Properties of a Web Page

Learn about the basic concepts of a web page, including HTML, HTTP, static and dynamic pages, web servers, file transfers, web addresses, and media types.

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Basic Properties of a Web Page

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  1. Basic Properties of a Web Page Teppo Räisänen LIIKE/OAMK

  2. Client-server model

  3. Basic concepts • The Web • World Wide Web, WWW • A system of interlinked hypertext documents accessed via the Internet • Hypertext • is text displayed on a computer or other electronic device with references (hyperlinks) to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices.

  4. Basic concepts • HTML • HyperText Markup Language • HTML is used to represent the content (text, images) and the links in the Web

  5. Basic concepts • HTML can be used to create HTML-documents • Document name ends with .htm or .html • One HTML-document contains one Web page

  6. Basic concepts • HTTP • HyperText Transfer Protocol • Networking protocol that is used to transfer the web pages from server to client • http://www.oamk.fi/

  7. Basic concepts • Web pages can be static or dynamic • Static web page • The content of the page does not change • Dynamic web page • The content of the page can change as it is created based on some criteria

  8. Web Server (1) • The development work of static web pages can be implemented using a local workstation • Dynamic pages often require server end some more testing • At the publishing stage the pages must be transferred to a public server • File transfer

  9. Web Server (2) • The instructions of file transfers are usually provided by the Internet Service Provider (ISP) • Web server space can be obtained e.g. from: • ISP (Baana, Elisa, Saunalahti…) • Work/Study organization • Web hotel service

  10. File Transfers • The file transfers can be committed using: • A FTP client (CoreFTP, WSFTP, SSH Client) • A Web Editor (Dreamweaver, FrontPage) • FTP functionalities of a browser (restricted) • Browser based application provided by the ISP

  11. Web Material (1) • Besides HTML-pages browsers know how to work with • Image files • Sound files • Text files (e.g. .pdf) • Have a look at • http://www.oamk.fi/~teraisan/K1047BI/

  12. Web Material (1) • Many formats of files can nowadays be embedded within a web page • Flash, Java, Silverlight, … • The content needs plug-ins to work • If the plug-in is not installed an error message is displayed

  13. Web Material (2) • It is still to be remembered that • Not all file formats are supported by the browsers • Not all browsers support same kinds of file formats • Depending of the browser type the same kind of material (e.g. sound files) may be presented in a different manner

  14. Web Material (3) • Companies providing free server space may restrict the use of some file formats: • Mp3 • .zip, .rar

  15. Web Addresses (1) • The initial part of a web address consists of the protocol and the server’s name (e.g. http://www.oamk.fi) • The following parts of the address reveal the site’s hierarchial structure (e.g. http://www.oamk.fi/english/intra/) • Have a look at file structure at • http://www.oamk.fi/~teraisan/K1047BI/

  16. Web Addresses (2) • The web applications might generate complex addresses like • http://pan.kaha.oamk.fi/intra/harjoitt.nsf/0bbcbb05402f06c24225695800354d8c/03cc4567f8fa7869c22570b5003eb77b?OpenDocument • In principle the protocol definition (http://) is a part of web address • The part of address that declares the actual file (e.g. index.htm) is called a relative address

  17. Web Addresses (3) • The names of the relative addresses should be kept simple: • myhobbies.htm vs. abcsd1789234.htm • One might have to pronounce the addresses during phone conversations • Relative addresses belonging to the same group may be named logically • letter11012006.htm, letter 11012006…

  18. Web Addresses (4) • http://www.googleguide.com/web_address.html

  19. Media Types • The server will send information of a requested files media type • The browser will use the information about the media type to decide, how to present the file (Open MediaPlayer, open Acrobat Reader etc.) • Sometimes the browser doesn’t know how to treat a file, so a mp3 file might be displayed in a browser window…

  20. File and Media types

  21. File Types • Even with faster connections, the large file sizes are still problematic • It is usually more sensible to provide a link to a large file instead of embedding the file into a HTML page • For large images, sounds, and videos one might want to provide thumbnails and preview opportunities.

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