E N D
The applications of science have built man a well-supplied house, and are teaching him to live healthily therein. They have enabled him to throw masses of people against one another with cruel weapons. They may yet allow him truly to encompass the great record and to grow in the wisdom of race experience. - V. Bush, Atlantic Monthly, 1945
Presenting Information • HTML(http://www.w3schools.com/html/) (Chapter 2) • XML(http://www.w3schools.com/xml/) • World-Wide Web(http://www.w3.org)
Hypertext Markup Language • A document formatting language that supports: • Formatted text • Images • Hyperlinks to other documents • Working with HTML documents: • Web browsers display HTML documents • Editors create/modify HTML documents • HTML marks up a document’s text using tags.
HTML Document Structure <!DOCTYPE Document_Type_Specification> <html> <head> <title>Title_Bar_Text</title> </head> <body> Web_Page_Elements </body> </html>
HTML Tags – Title bar <head> <title>Acme Traders</title> </head>
<h1 align="center">Acme Traders</h1> <b>Grand Rapids, Michigan, USA</b> <i>Phone: 1-800-555-5555</i> <h2>Customer Service</h2> HTML Tags – Text Formatting
HTML Tags – Lists <ul> <li>How to Order</li> <ol> <li>Select Items</li> <li>View Your Shopping Cart</li> <li>Check Out</li> </ol> <li>Shipping and Returns</li> <li>Check on Your Order</li> </ul>
HTML Tags – Images <img src=“images/acme_septimus_t.gif" height="200" width="200“ />
HTML Tags – Other graphics <hr size="5" noshade>
HTML Tags – Hyper Links <a href="planner.htm"> <h2>Planner</h2> </a>
HTML Special Characters <small>©acme.org (7/4/03)</small>
HTML Comments <!-- Company logo/horizontal rule -->
HTML Tags – Tables <table align="center" border="5" cellspacing="3" cellpadding="5"> <tr> <th>Item Number</th> <th align="left">Description</th> <th>Image</th> </tr> <tr> <td align="center" valign="top">1</td> <td valign="top">Magnet</td> <td><img src=“images/magnet.jpg"></td> </tr> <tr> <td align="center" valign="top">2</td> <td valign="top">Umbrella</td> <td><img src=“images/umbrella.gif"></td> </tr> </table>
XML • Extensible Markup Language • An extendable generalization of HTML • You define your own tags using a document type definition (DTD) • Is fast becoming a standard information interchange format.
Document type definition: <?xml version="1.0"?> <!ELEMENT note (to,from,heading,body)> <!ELEMENT to (#PCDATA)> <!ELEMENT from (#PCDATA)> <!ELEMENT heading (#PCDATA)> <!ELEMENT body (#PCDATA)> An Example XML data file: <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE note SYSTEM "InternalNote.dtd"> <note> <to>Class</to> <from>Keith</from> <heading>Reminder</heading> <body>Don't forget project 6!</body> </note> Example from www.w3schools.com July, 2003
Tim Berners-Lee (1955- ) World Wide Web • late 1980’s • Developed the key elements of the WWW: • URL - universal resource locators • HTTP - hypertext transfer protocol • HTML - hypertext markup language • Provided the basis for an implementation of Vannevar Bush’s vision of the memex. Image from www.adlandia.dk July, 2003
What’s the Big Idea How Big is the WWW? • Who really knows? • “surface” web - ~50 terabytes • “deep” web - ~7500 terabytes • Key challenges for the 21st century: • Mining • Filtering