HOME » WEB DEVELOPMENT » AUTHORING AND PUBLISHING

ABOUT THE WORLD WIDE WEB

Glossary of Terms: Client Domain E-mail File Transfer Protocol HTTP Internet Service Provider Protocol Server URL Web browser Web server

What is the Internet?

The Internet is a network that interconnects millions of computers around the world. Physically, the Internet consists of clients (individuals using personal computers to connect to the Internet), servers (computers that provide services such as e-mail or file storage for groups of clients), and the network hardware that connects them (wires, switches, routers, modems, transoceanic cables, and even satellites). Access to the Internet is provided by an Internet service provider (ISP), which operates the network hardware to connect a large number of clients to the Internet.

At a more abstract level, the reason the Internet works is because of its many protocols, or standards for exchanging information. International organizations such as the Word Wide Web Consortium continually negotiate and update protocols for transferring e-mail, documents, files, images, and so on. These standards allow computers anywhere in the world to "decode" information that originated anywhere else. Thus, Internet clients and servers can exchange almost any kind of digitized information.

What is the World Wide Web?

One use of the Internet is the World Wide Web -- usually just called "the Web." At heart, the Web is simply a way of publishing information (such as documents) so that it is easily accessible by others connected to the Internet. This is accomplished by placing the information on Web servers. A Web server is a computer connected to the Internet and configured to make the information it stores available to other computers "through the Web." Clients use software called a Web browser (such as Netscape Navigator or Microsoft Internet Explorer) to view information stored on any Web server.

The Web contains millions of documents, and it would not be very useful were it not possible to retrieve each of them by name. For this reason, every object on the Web has a unique Web address, called a Uniform Resource Locator (URL). A document's URL consists of the protocol that will be used to retrieve it (such as HTTP), the name of the Web server on which it is located (called its domain name), its path (the directory or folder in which it is located), and its file name. On most Web servers, URLs are case sensitive, and their spelling and punctuation must be exactly right. For example, the following URL uniquely identifies the Web page you're looking at now:

What are Web pages, Web sites, and home pages?

Try it: To see the text and HTML codes that make up the Web page you're viewing, click on View | Page Source.

The Web can be used to publish many kinds of files, but the most common are Web pages. A Web page is simply a plain text file to which codes have been added according to a standard called Hyper-Text Markup Language (HTML). The codes (also called "tags") control formatting such as paragraph breaks, fonts, page layout, and tables. When you access a Web page, your Web browser interprets these codes and displays the resulting formatted document for you to look at or print.

When a Web page includes items such as photographs, these are not contained in the Web page itself. Rather, the Web page contains HTML codes that cause your browser to retrieve the necessary images and assemble them on your computer screen. This is possible because every image stored on the Web also has its own unique URL.

A collection of related Web pages and other materials is called a Web site. Usually, a Web site is organized around a home page, which is a Web page that provides access to all or most of the other Web pages in the Web site. Large Web sites may contain other Web sites with their own home pages; for example, the Georgetown Web site contains hundreds of departmental and individual Web sites.

Because every Web page has a unique URL, it is possible to create links that users can follow between Web pages. A Web page can contain many links, which are usually displayed as blue, underlined text. Each link specifies the URL of another Web page to be retrieved and displayed in your browser. Here's what happens when you click on a link:

As you can see, it can take significant time to retrieve and assemble a large Web page such as one that contains many images. This is one reason why it is often preferable to keep Web pages relatively short and simple.

As a review, the diagram below shows the components that are involved as a Web page makes its way to you through the Web:

How does Web publishing work?

From the point of view of someone creating a Web site, the Web publication process generally involves the following components:

A wide variety of software tools may be involved in these steps. Generally, Web authoring involves the use of a Web editor, such as Macromedia Dreamweaver or a more programmer-oriented tool such as Allaire HomeSite. In the Web publishing step, Web pages are transferred to a Web server where they will become available to the world. This is typically accomplished using a file transfer tool built into a Web editor, or a stand-alone tool such as SSH Secure Shell. The developer may have the option of adding additional Web hosting features on the Web server, such as access restrictions.

At this point you may want to read about Web authoring and publishing as well as Web hosting services at Georgetown.

What is a Web application?

In your travels through the Web you will encounter Web sites that do more than just publish documents or images for you to see. For example, you might buy a book or search a library database online. Each of these functions is driven by a Web application. Web applications are software programs written to allow Web servers to respond dynamically to user requests.

Some Web applications are sold commercially, but most are still created by individual programmers in Web application development languages such as Perl, ColdFusion, or ASP. Web application development requires programming skills and usually also database design skills, but simple Web applications can be created by beginners as well.

At this point you may want to read about resources for Web application development at Georgetown.

Further reading

To learn more about the history of the Web, as well as new Web technologies, visit the Web site of the World Wide Web Consortium (W3C). The W3C coordinates the development of standards and technologies for the Web.