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HTML and Hypertext The workings of the web

HTML and Hypertext The workings of the web. Lecture 7. HTML : Hypertext mark-up language. HTML is the most widely used method of structuring a hypertext document Web pages are written in HTML and use URL’s (universal/uniform resource locators) to form links to documents and/or files e.g

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HTML and Hypertext The workings of the web

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  1. HTML and Hypertext The workings of the web Lecture 7 CP2022 Multimedia Internet Communication

  2. HTML : Hypertext mark-up language • HTML is the most widely used method of structuring a hypertext document • Web pages are written in HTML and use URL’s (universal/uniform resource locators) to form links to documents and/or files e.g • http://www.andysloane.com • HTML document • A simple text based document with tags • Can be created with simple text editors • Notepad in Windows • via tools which generate HTML • Word, Dreamweaver, etc CP2022 Multimedia Internet Communication

  3. Document Structure • Simple HTML documents can start with <html><head></head><body> • and finish with </body></html> • In between <head> and </head> is where the document title /main heading info is placed • the main detail content of the page is placed in between <body> and </body> CP2022 Multimedia Internet Communication

  4. A Simple Document • Simple HTML document: <html><head></head><body> This is my home page! </body></html> • It will appear on screen as This is my home page! • HTML can specify graphics, video, and audio content as well as simple text for the web page CP2022 Multimedia Internet Communication

  5. HTML Tags • HTML tags are always in angled brackets and usually tag the start and finish of a section of text - to specify attributes • e.g.: <b> Hello </b> • tags the word hello so that it will appear onscreen as bold • The bold <b> italic <i> tags are illustrated in this example I am <i>very</i> interested in <b> HTML</b>. • To give: I am very interested in HTML. CP2022 Multimedia Internet Communication

  6. More about Tags …. • Apart from the bold and italic tags there are tags to change the font size and colour as well as to underline your text • When Web browsers read HTML files they always ignore ‘usual’ paragraphs and line endings in the document • You have to use special tags to declare paragraphs • The <p> tag signifies the start of a new paragraph (and </p> denotes end of paragraph) CP2022 Multimedia Internet Communication

  7. Paragraphs and lists • There are special tags which operate on whole paragraphs at a time • These tags allow you to give instructions for displaying paragraphs, such as whether they should be centred, left justified or right justified • HTML has a range of special tags to allow you to set up lists • The list styles include numbered lists and bulleted lists …….. experiment ! CP2022 Multimedia Internet Communication

  8. HTML tags Tag Description NN IE <!--...--> Defines a comment 3.0 3.0 <!DOCTYPE>  Defines the document type     <a> Defines an anchor 3.0 3.0 <abbr> Defines an abbreviation 6.2   <acronym> Defines an acronym 6.2 4.0 <address> Defines an address element 4.0 4.0 <applet> Defines an applet 2.0 3.0 <area> Defines an area inside an image map 3.0 3.0 <b> Defines bold text 3.0 3.0 <base> Defines a base URL for all the links in a page 3.0 3.0 <basefont> Defines a base font 3.0 3.0 <bdo> Defines the direction of text display 6.2 5.0 <big> Defines big text 3.0 3.0 <blockquote> Defines a long quotation 3.0 3.0 <body> Defines the body element 3.0 3.0 CP2022 Multimedia Internet Communication

  9. HTML Tags - sources • There are good examples/tutorials at http://www.w3schools.com/tags/default.asp • Full definitions at http://www.w3.org/TR/REC-html40/ • HTML 4 is now given as XHTML 1.0 CP2022 Multimedia Internet Communication

  10. Pictures • Pictures can be included in web pages - using the <img> tag • Important - the pictures themselves are not stored in the HTML document ; just the mark-up language • image is stored in separate file • e.g. <img src=“logo.gif” alt=“logo image”> this displays the ‘logo’ graphic or the text:- ‘logo image’ (if image not accessible) CP2022 Multimedia Internet Communication

  11. Hyperlinks • You can include links in your document (formed using tags) • Links are words or pictures which when ‘clicked on’ take you to another web page or open up a file (audio/video for example) • There is a special tag <a href=“xyz”>text or picture </a> • the text / picture is now defined as a link (to the location specified by ‘xyz’ - usually a URL address of a page/file) CP2022 Multimedia Internet Communication

  12. Hyperlink example • Using text as the clickable link e.g. <a href=“http://www.scit.wlv.ac.uk/~cm1950/ CP2022/lect7v4.ppt"> Lecture 7 - HTML and hypertext</a> • Using an image as the clickable link e.g. <a href ="http://www.andysloane.com/"> <img src="picture.jpg"></a> CP2022 Multimedia Internet Communication

  13. Using style <?xml-stylesheet href= "http://www.w3.org/StyleSheets/ TR/W3C-REC.css" type="text/css"?> <?xml-stylesheet href="#internalStyle“ type="text/css"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>An internal stylesheet example</title> <style type="text/css" id="internalStyle"> code { color: green; font-family: monospace; font- weight: bold; } </style> </head> <body> <p> This is text that uses our <code>internal stylesheet</code>. </p> </body> </html> CP2022 Multimedia Internet Communication

  14. Style example – Screen output CP2022 Multimedia Internet Communication

  15. Cascading Style Sheets • Often used by software to create web pages • Allows full control of page display • Definitions available from • http://www.w3.org/Style/CSS/ CP2022 Multimedia Internet Communication

  16. Evolving techniques • The Web is evolving…… • Research into semantic web • Intelligent use of web-based resources allowing • Re-use of information by different • applications • organisations and • users • Uses resource description framework (RDF) • http://www.w3.org/RDF/ CP2022 Multimedia Internet Communication

  17. Summary • Basic HTML is used to specify the content and layout of web pages • HTML documents contain text plus tags to tell the web browser how to format the text • The documents can also contain tags for links to other pages and files (such as audio/video), and to display still images as part of the page • Web page creation and management techniques are evolving rapidly CP2022 Multimedia Internet Communication

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