The World Wide Web

   

The World Wide Web ”or simply the Web ”is a part of the Internet that provides information, using documents that include one or more of these components :

  • Formatted text. Formatted text makes it more attractive and easier to read and understand. (Well, it's supposed to anyway.)

  • Images. Graphic images make Web information more visually appealing or can provide information that can't be provided with text. Other multimedia elements ”including sounds, movies, and even interactive games ”can also be found on the Web.

  • Hyperlinks . Links enable you to navigate from one piece of information to another with just a click.

  • Forms. Fill-in forms enable you to provide information that can be used to find information that interests you (in the case of a search form) or stored in a database (in the case of a database entry form).

Hyperlinks

Text or graphics you can click to view other information. Hyperlinks are often referred to as just plain links . Text links are sometimes called hypertext links .


A lot of people think the World Wide Web is the same as the Internet. This isn't true. The World Wide Web is only part of the Internet. The Internet is far more than just the World Wide Web.

A [Very] Brief History of the World Wide Web

The Web was created in the early 1990s by Tim Berners-Lee and Robert Cailliau, two members of CERN, a physics research facility in Switzerland. It began as an academic project to make it easier for physicists to share information. Although Gopher, another information publishing feature, was already on the Internet, the formatted text and hyperlinks on Web pages made it a more flexible information distribution tool.

Web Page

A document on the World Wide Web. Normally created with HTML, Web pages can be any length and are viewed with Web browser software.


The Web was used primarily by these researchers and scientists until around 1993 when NSCA Mosaic hit the scene. Written by Marc Andreessen (later a founder of Netscape Communications), the Mosaic Web browser was stable, available on multiple platforms (other Web browsers were available only for Unix workstations), and free. People ”and the media ”began to notice the Web. Soon all kinds of organizations, from individuals and clubs to multinational conglomerates, began to publish and access information on the Web.

Web Browser

A software program used to view and navigate Web documents.


As the Web began to gain momentum, other Web browsers were developed ”notably Netscape Navigator and Microsoft Internet Explorer. "Browser wars" ensued, but that's another story.

Originally, Web documents were based entirely on HTML (hypertext markup language), a system of tags or codes that determines how information in the document looks or behaves. As Web browsers, publishers, and users became more sophisticated, additional languages were added to the Web publisher's toolbox, including DHTML, Java, JavaScript, VRML, and XML. (I discuss all of these Web publishing technologies in Chapter 8.) As a result, there is more control over the appearance of information, more dynamic information, and a greater level of interactivity on the part of the Web user than ever before.

Today, there are billions of Web pages on the World Wide Web. According to some sources, the Web is doubling in size every year, with an estimated 10 million sites as of January 2000. Not bad for a little academic project in Switzerland, is it?

How the Web Works

To really understand the Web, you need to know a little about how it works. Although you could sit down with the System Administrator of a big site like Yahoo! or MSN and learn all kinds of technical details about protocols, packets, and proxies, you don't need that level of understanding. (I don't either. In fact, few people do.) Instead, allow me to tell you what you need to know in wlanguage we can all understand.

A Look at the Server

Every Web site lives on a Web server , a computer set up to "serve" Web pages and related information. The Web server has a direct connection to the Internet and a static IP address that is associated with the Web site's domain name . The Web server software runs silently, waiting for requests from Web browsers.

Web Server

A computer that is connected to the Internet (or an intranet) and runs software capable of handling HTTP requests.


IP Address

A unique numerical address assigned to a computer on the Internet.


Domain Name

A name associated with an IP address. peachpit.com and wickenburg-az.com are two examples of domain names .


On the server's hard disk are all the documents that make up the Web site. This usually includes HTML documents, images, and multimedia elements. (The server may also include programs called CGIs that enable it to perform tasks such as processing forms or searching for data, but we don't need to go into that right now.)

There are very few cross ”platform compatibility issues on the Web. Any kind of computer ”Macintosh, Windows (any flavor), or Unix ”can serve Web pages to any kind of computer.

A Browser Knocks

A Web user accesses the Web using Web browser software. He runs the software and if necessary, the software establishes an Internet connection. The user then tells the Web browser to open a URL or Web address.

URL (Uniform Resource Locator)

An Internet address that includes the protocol required to open the document. For example, http://www.wickenburg-az.com/weather/weather.html is a URL.


Every URL has several parts . The first part provides the type of request. For Web pages, this is usually http . (In case you're wondering, this stands for hypertext transfer protocol .) The second part provides the name of the server. This usually begins with www , but doesn't have to. For U.S. sites, this often ends with .com , but it can also be .org , .net , or other dot- letters . The last part provides the path and name of the Web page. If this last part is omitted, the Home page is assumed.

Home Page

The main entry page of a Web site. Think of this: The home page is to a Web site as a front door is to a house.


Tip

You can learn more about URLs in "A Beginner's Guide to URLs" at http://www.ncsa.uiuc.edu/demoweb/url-primer.html.


When the Web user enters his request, his Web browser begins a conversation with the domain name server he specified in his Internet configuration. It basically says, "What's the IP address for this domain name?" The domain name server searches its database and sends the IP address back to the Web browser. The Web browser can then find the proper Web server and present its request.

The Web Server Responds

The Web server, which may be busy or idle depending on how active the site is, gets the browser's request. If it can find the requested page, it begins sending the file's data to the Web browser. If the file includes references to other files ”such as images ”it sends them, too. Each request it handles is referred to as a hit .

Page Hit

A request for a Web page document. A page hit can result in additional hits to images and other files referenced in the Web page.


If the server can't find the requested page, it sends an error message to the Web browser. You may have seen this as an "Error 404" message.

The Page Appears

The page begins to appear in the Web browser window. How quickly it appears depends on several factors:

  • How fast is the user's connection to the Internet?

  • How fast is the server's connection to the Internet?

  • How large are the files that make up the Web page?

  • How many requests is the server handling at once?

  • How much traffic is on the 'Net, slowing things down?

(Depending on how the server is configured, it can send multiple files at the same time ”even to multiple Web browsers ”so with fast connections, page elements can pop up quickly.)

The User Follows a Link

When the user clicks a link on the page, he initiates another request based on the URL embedded in the link. If the request is to a different domain name, the Web browser talks to the domain name server again; if it's to another page on the same site, the request goes straight to the Web server.

Putting It all Together with an Example

My Web server is a good example. It's a Power Macintosh running WebSTAR Web server software. It has an ISDN connection to the Internet and is assigned the IP address 207.138.23.226 . That address is associated with the domain name wickenburg-az.com . All day and night long, WebSTAR is running, waiting for a chance to serve up Web pages.

On the server's hard disk are all the files that make up the wickenburg-az.com Web site, including HTML page files, JPG and GIF image files, and a few PDF document files. (There are even a few plug-ins and CGIs, but we don't need to go into that now.)

Now suppose my brother Norb, who lives in New Jersey, wants to see how the weather is in Wickenburg. Norb launches his Web browser and it connects to the Internet. He enters the URL for the wickenburg-az.com Current Weather page into his Web browser: http://www.wickenburg-az.com/weather/weather.html.

Norb's browser contacts the domain name server he specified when he set up his Internet configuration. The domain name server tells the browser that the information it needs can be found at 207.138.23.226 . The browser then contacts the Web server at that address and requests the file named weather.html in the folder named weather .

My Web server looks for the file and finds it. It begins sending the HTML document. As it sends the file, it sees references to image files that are part of the Web page. It sends those, too. All the while, it's handling other requests for other pages and images. (It keeps pretty busy.)

Although my Web server's connection to the Internet is only 128 Kbps (relatively slow as far as servers go), Norb's connection is only 33.6 Kbps. So no matter how fast my server sends files, the fastest they can reach Norb's browser is 33.6 Kbps. (And that's if the 'Net isn't too busy.) Still, the page appears pretty quickly, primarily because it doesn't contain a lot of large graphics. (I tell you more about my Web design philosophy and why I stick to it in Chapter 7.)

Kbps (Kilobits Per Second)

A unit used to measure connection or transfer speeds. Refers to thousands of bits per second.


   


Putting Your Small Business on the Web. The Peachpit Guide to Webtop Publishing
Putting Your Small Business on the Web
ISBN: 0201717131
EAN: 2147483647
Year: 1999
Pages: 83
Authors: Maria Langer

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