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06-00 Browsers are quickly becoming the primary user interface on the Internet.


06-01

The basic concept is that a browser on your machine (Netscape in this example) talks to an information server elsewhere on the internet. Netscape generally talks to HTTPd servers (Hyper Text Transfer Protocol Daemon) although it can also talk to Gopher and FTP servers.

The addressing form for information is called the URL (Uniform Resource Locator). In this example http://www.xxx is the URL. The collection of servers all over the world is a distributed database called the World Wide Web.


06-02

This is a typical page you might see viewing information with a browser like netscape. Note there are various sections of different-color text and buttons interspersed in the document. These are hyper-links and if you point the mouse at a link and click once you direct the browser to follow that link (a URL) and display the information that link points to. Links can point to hypertext documents (as displayed above), audio clips, pictures, movies, and programs to download.


06-03

The vast network of servers available on the World Wide Web is like a virtual disk attached to your machine. You access the information by clicking on hyperlinks.


07-00

How do browsers work?


07-01

When you click on a hypertext item the browser program sends a request to the computer specified in the URL to send that information. The HTTP server then sends the entire document and any pictures imbedded in that document. The browser then displays that document and allows you to select any of the hypertext links in that new document.


07-02

A hypertext page can give you links to additional text, images, other hypertext pages, movies, or sound bytes. Simply click on the highlighted text, the icon, or the image to view the information.


07-03

Position the cursor on the link item and the click the mouse. Clickable things are usually easy to spot, but it you watch the bottom of your screen netscape will print the URL when you are pointing to a clickable item.

Images can also be clickable and page designer can do different things based on what spot on the image you have clicked.


07-04

When a hyperlink is click the browser transparently accesses some other computer and presents the information from that other computer with its hyperlinks.

Hyperlinks can be used to provide a user interface or menu type of operation or they can simply be used like references in a journal. The difference lies in the purpose of the page. Many pages on the World Wide Web are simply gateways to other information while others are intended to convey information.


07-05

The hyperlink destinations (URLs) in a hypertext document can point to multiple other machines or to multiple places on the same machine. The information you are viewing could be coming from anywhere in the world.



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