"Chapter Nine "Looking at Information on the Internet

Chapter Nine
Looking at Information on the
Internet
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9-1 World Wide Web
Understanding the World Wide Web A web server(generally an ISP) provides the service of hosting or
storing a company’s or a person’s web site. A web site is a collection of pages containing information, similar to
a promotional booklet about a company. In order for a web server to be able to communicate with other
computers, it must use the Hypertext Transfer Protocol (HTTP). A web server typically hosts many web sites.
The collection of all web sites hosted by all the web servers connected to the Internet is referred to as the World
Wide Web, often referred to simply as “The Web”. “Hypertext” refers to the technique of accessing the web
pages using hyperlinks. In essence, these hyperlinks allow you to link to other web pages on the same web site
or another web site where you will find other text, pictures, media, etc. Part of the popularity of the Web is due
to the attractive way that web pages are displayed — web pages use color, graphics and photographs. The
interesting feature of the Web is that the web pages stored on a web server have no formatting. The software on
the user’s computer (called a browser) has to format the page before it is displayed on the screen. The formatting
instructions are included in the text of the web page and are written in a language called Hypertext Markup
Language(HTML).
9-2 Web Page Elements
A typical web page will contain some standard elements, as shown in the following screen:
URL
The Uniform Resource Locator identifies where you can find information (the web site address to go to), or you
can enter text to display a list of matching web sites.
Picture
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Web pages can contain pictures that are either graphics or photographs. Some pictures are set up to be static
(always shows and stays in this location), others may animate, or are hyperlinks to other web pages, web sites ,
or another action such as run a vide
Field
Many web pages contain forms where you can enter information into the fields on the form. The information in
the fields will then be sent to the web server for processing. Most web pages contain at least one field (usually
designed to help you search for an item on that web site).
Button
An interactive graphic that when clicked, an action will take place. In this example, clicking on the button will
send the search information to the server.
Advertisement
Companies pay for the privilege of advertising on a popular web page (i.e., gets many “hits”). These ads are
typically graphics and often animated. The intent is that you will click on the graphic to view the advertising
company’s web page.
Status Bar
The status bar tells you what the software is busy doing or which web page or site is displayed if you click on a
specific hyperlink. You can use this bar as a visual clue to whether the web browser has completed the display
for the web page or if you are no longer connected to the Internet.
Hyperlink
Text or a graphic that has a URL associated with it. In general, when you place the mouse pointer over a
hyperlink, the pointer changes to a pointing hand . If you then click with the mouse on the link, the web browser
software will then try to connect to the server corresponding to the URL and retrieve the information or web
page. Some hyperlinks are underlined, usually with the intent of getting your attention quickly to click on that
link, as required. Other hyperlinks appear with underline or another effect such as if a light was turned on only
when you move the mouse and hover over the text or picture. Most web sites will also display a hyperlink in
another color to show you have already visited this link (site).
Although most web pages will have one or more pictures, the pictures are not strictly part of the page. The
pictures are stored separately on the web server. The web page only contains place holders where the pictures
are to be placed on the web page. When the browser receives a web page from a web server, it first formats the
text of the page using the HTML instructions included on the page. The pictures take longer to arrive from the
server, so they are placed on the page by the browser after the page has already been formatted, sometimes
several seconds will go by before all the pictures have displayed.
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9-3 Uniform Resource Locator (URL)
There are many computers connected to the Internet, and a computer can communicate with any other
computer provided that 1) you know the address (number) of the other computer, and 2) that both computers
speak the same protocol (language). The Uniform Resource Locator (URL) consists of these two parts.
For example, if you want to view the Netscape web site, the URL would be:
http://www.netscape.com
If you want to view Microsoft’s file transfer server, the URL would be:
ftp://www.microsoft.com
A web browser software is used to communicate with any type of server connected to the Internet. The browser
uses the protocol portion of the URL to set up its internal configuration so that it can connect and communicate
with the type of server selected. In the examples shown here, it was a web server in the first example, and an ftp
server in the second example.
In most cases, when entering an URL with a “www” in the web address (e.g., www.ccilearning.com), you do not
need to type in the protocol portion if you want to go to that web server. The URL, by default, will automatically
try to find the web server for that web site address if the www is not entered. However, if you want to go to a
specific type of server, it is crucial that you enter the protocol at that time