Navigating The World Wide Web Lesson 1

What is the World Wide Web? Timothy Berners-Lee and other researchers at the CERN nuclear research facility near Geneva, Switzerland laid the foundations for the World Wide Web, or the Web, in 1989 They developed a system of interlinked hypertext documents that allowed their users to easily navigate from one topic to another The Internet is a global network of computers linked by high-speed data lines and wireless systems The World Wide Web (Web or WWW for short) is just one of several services provided by the Internet, which consists of a system of interconnected networks Hypertext is a way to organize information so that you can click links to jump from one piece of information to another

How the World Wide Web Works Hypertext—can read and navigate text in non linear way Graphical and Easy to Navigate—versus early days of the Internet Cross-platform Distributed—information not located in one centralized location Dynamic Information Interactive Information

Linear versus hypertext documents When you read a book, you follow a linear progression, reading one page after another With hypertext, you progress through pages in whatever way is best suited to you and your objectives Linear versus hypertext documents

Web Pages Each document on the World Wide Web is referred to as a Web page A Web site is a related collection of Web pages A home page is the first document users see when they access a Web site

Web Servers Web pages are stored on a Web server, or host, which is a computer that stores and sends (serves) requested Web pages and other files

Web Pages and Web Servers

Web Browsers A Web browser retrieves the page from the Web server and renders it on the user’s computer or other device The earliest browsers, known as text-based browsers, were incapable of displaying images

Understanding URLs To create a link to a resource on the Internet, you need to know its URL A Uniform Resource Locator (URL) specifies the precise location of a resource on the Internet A protocol is a set of rules defining how information is exchanged between two resources

Understanding URLs Your Web browser communicates with Web servers using the Hypertext Transfer Protocol (HTTP) The URLs for all Web pages must start with the scheme “http” Other Internet resources use different protocols and have different scheme names

Common Communication Protocols

A sample URL for a Web page Understanding URLs A sample URL for a Web page

Understanding URLs If a URL includes no path, then it indicates the topmost folder in the server’s directory/folder tree If a URL does not specify a filename, the server searches for a file named “index.htm” or “default.htm”

End of Presentation