Unit 2 The World Wide Web Section B Tim Berners-Lee Photo source: Tim Berners-Lee personal web page NCSA at the University of Illinois Photo source: Wikipedia

Chapter 1, Slide 2Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 2 World Wide WebWorld Wide Web - a huge set of Internet pages that use hypertext to reference each other HypertextHypertext is much like an online encyclopedia Can click hyperlinks that refer to other pages, taking you from one page to another and anotherhyperlinks Each individual display referred to as a Web pageWeb page Internet usage exploded in the 1990’s due to the creation of the World Wide Web The Web now dominates the Internet But still a subset of overall activity on the Internet

Chapter 1, Slide 3Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 3 Tim Berners-Lee conceived the Web by applying the idea of hypertext to the Internet in 1991 Creates hypertext transfer protocol (HTTP)HTTP TCP/IP protocol still governs rules of data transmission But HTTP protocol sets the rules for interpreting and displaying Web pages transmitted across the Internet Defines Hypertext Markup Language (HTML)HTML Rules to follow when encoding web pages A formatting language, not a programming language

Chapter 1, Slide 4Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 4 Marc Andreessen and Eric Bina create Mosaic, the first graphical Web browser in 1993 Funded by the National Center for Supercomputing Applications (NCSA) at the University of IllinoisNCSA Expands on standards created by Berners-Lee Uses images in Web pages Written for Windows platform as well as Unix Internet usage takes off Source:

Chapter 1, Slide 5Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 5 Berners-Lee Didn’t create the Internet or the hypertext concept But was the 1 st to apply hypertext to the Internet Andreessen and Bina Didn’t create the World Wide Web But 1 st to combine images and text on the Internet And do it in an easy-to-use format for Windows They stood on the shoulders of others But they were in the right place at the right time with the right idea and the skills to carry it out

Chapter 1, Slide 6Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 6 Each Web page is basically a simple text file File holds Web page text & formatting instructions The formatting instructions are known as HTMLHTML Images stored in separate files referenced by HTMLHTML Each Web page is found at a unique address called a Uniform Resource Locator (URL) Often just called a web address… example below

Chapter 1, Slide 7Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 7 A Web site is a collection of related Web pages under a single domain name or IP addressdomain name Web sites are usually accessed by domain name For example, HCC’s web site is Web sites have a home page Initial page shown to a user Home page contains hyperlinks to other pages on the Web site A hand with an index finger pointing up is usually shown when scrolling over a link

Chapter 1, Slide 8Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 8 A Web server is a computer with the software needed to respond to web page requestsWeb server A Web server may host hundreds of Web sites, or just one If hosting many Web sites, each site kept in a folder Domain name maps to folder at server IP address In order to make a Web page available on the Internet, it must be transferred to a Web server

Chapter 1, Slide 9Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 9 Begins with the web page protocol Then identifies a Web server by specifying the domain name or IP address of the Web site Rest of URL is a file path but with forward slash Shows folder path from web site root folder to file Then specifies the name of the html file

Chapter 1, Slide 10Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 10 Web browsers provide users with software designed to view the World Wide Web A browser simply fetches & displays Web pages Popular Web browsers include: Internet Explorer – most heavily used by far Google Chrome Mozilla Firefox Both Chrome and Firefox are gaining users due to ongoing security issues with Internet Explorer

Chapter 1, Slide 11Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 11 Title bar shows current web page name. Address bar shows current URL and allows user to request a new URL. Menu bar displays names of pull-down menus providing options to save, print, copy, navigate between pages, and configure your web browser. Status bar shows the URL for any link you move your mouse over. Tool bar provides buttons for frequently used tasks Go button fetches web page typed in address bar Links to other web pages

Chapter 1, Slide 12Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 12 Back returns to previously displayed web page Forward allowed only after back button Displays web page you “backed” out of Home displays home page for your browser Favorites can be used to hold a list of web page URL’s you tend to visit frequently

Chapter 1, Slide 13Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 13 Print lets you print an entire web page Often useful to print just a portion of a web page Click and drag over portion of web page to print Click Selection in page range section of print dialog box Copy lets you capture text from a web page History shows URLs visited by that web browser It’s easy to save web page images to your disk Right-click on an image Select Save Picture As from the short-cut menu Beware of violating copyright laws!

Chapter 1, Slide 14Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 14 Make finding information on the web fairly easy Helps you locate web pages on a certain topic Enter a few key words that describe your search There are many different search engines Google is currently the most frequently used There are many other search engines including Microsoft, Yahoo, Ask, etc. Try the Advanced Search option if you’re not finding what you want

Chapter 1, Slide 15Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 15 Lets you be more specific about key words Find resultswith all of these words with any of these words with this exact phrase without these words For example, search for the name Russell Virgo Result includes lots of astrology sites Add the words horoscope astrology in the without these words box Most astrology sites removed from results

Chapter 1, Slide 16Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 16 Mixes web page text & formatting instructions Formatting instructions found inside signs Text to be displayed found outside signs Use this web page to test the following HTML :web pageHTML This is bold text. This is normal text. Appears as “This is bold text. This is normal text.” Bold tag makes all text that follows bold Bold text continues until an end bold tag Tags do not appear in web page text shown to user

Chapter 1, Slide 17Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 17 Begin with to identify as an HTML file Use to set up title bar text Use to start text for rest of page Don’t forget to terminate each tag Use Notepad (in Accessories) to type in this text My First Page How cool is this… my first web page! Save file in Notepad with name FirstPage.html

Chapter 1, Slide 18Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 18 Use Windows Explorer to find your HTML file Double click file to display in Internet Explorer Edit the file in Notepad to add before the word cool & after it Save the file in Notepad Click the Refresh button in Internet Explorer Your web page reflects the change just made Refresh Button

Chapter 1, Slide 19Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 19 Bold - Italics - Underline - Center text on page - Change font size Where nbr is from 1 to 7 and color is red, blue, yellow, etc. Insert a hyperlink Text for link that a user sees For example, the URL for the HCC home page is

Chapter 1, Slide 20Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 20 The following tags do not require a terminating tag Start a new line - Start a new paragraph - Insert an image into a web page Where filename.ext is the name of a file containing an image Insert a horizontal line Where nbr is length of line in points Align can be left, right, or center Color is a standard color such as blue, red, yellow, etc.

Chapter 1, Slide 21Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 21 Tables are often used in HTML to align items begins a table starts a new row of the table starts a new column of the table Each of these tags must be terminated An example: row 1 column 1 row 1 column 2 row 2 column 1 row 2 column 2

Chapter 1, Slide 22Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 22 Head and title tags Font and center tags hr tag Hyperlink tag 2 column table used for text and pictures Left column text uses font tag Right column picture uses tag

Chapter 1, Slide 23Starting Out with Visual Basic 3 rd EditionIntroduction to ComputersUnit 2B – The World Wide WebSlide 23 A Web page must reside on a Web server to be viewed on the World Wide Web In order to publish a Web page, you must have space allocated to you on a Web server Many ISPs provide customers with free Web space Contact your ISP or read their information to learn how to gain access to your Web space Must download an FTP (File Transfer Protocol) program to transfer your Web page to a serverFTP