In this guide we will see how the Web works, HTML-HTTP, partial and complete URL, protocols and domains.

WWW CHARACTERISTICS

The World Wide Web provides us with the technology to connect us, by means of an attractive interface you can browse, to the huge collection and resources of the Internet. This electronic on-line universe is sometimes called ciberspace.

The programme we use to surf the Web, the browser, uses multimedia technology via the Internet to provide the user with a full and attractive experience.

The WWW appeared because of the amazing size of the Internet. There is so much information to access that it is very difficult to find what we want and use the Internet. The Web is the concept that best uses it's resources.

• First of all, because through the use a good browser we can surf without needing to know, remember or write the addresses of the places we visited.

• Secondly because it provides links related to the current page context.

• Thirdly because it gives the user a comfortable interface that uses the latest multimedia technology.

¿HOW DOES THE WEB WORK?

The Web works in a very simple way. The transactions have four fases:

1 - Connection: the client tries to connect with the server. The status bar of the browser usually shows the legends Conection with… /Transfering data... etc...
2 - Request: the client sends the request and protocol that will be used.
3 - Answer: the server sends the answer.
4 - Close: ends the 'dialog'. The browser then shows the requested data according to their format. (Text, graphics, audio, etc...)

Usually the browser shows an HTML (Hypertext Markup Language) document: This is the computer language in which Web pages are written. These documents are usually stored in WWW servers that use HTTP: Hypertext Transfer Protocol

URL ADDRESSES

Every resource on the WWW has a URL address: Uniform Resource Locator. This address is the location of the file on the Internet. The links we see in an HTML document contain the information of the URL they represent. The information that a URL contains allows us to 'jump' from one place on the Web to another by clicking on the link without needing to know the physical name of the file or its location. When we place ourselves over a link, the browser's status bar shows us the linked URL.

A URL consists of four separate parts which, when combined, define the location of the file or service on the Internet. These parts are: Protocol, Domain, Path and Filename. (The last two are called access route).

Protocol: This tells us the type of resource or access method to the address. The main protocols are:

http: a hipertext document or directory
gopher: a gopher document or menu
ftp: an ftp server
news: a news group
telnet: a telnet system
wais: a data base
file: a file on a local disc

Domain: (domain name or server) This is the server address that contains the data the link points to.

Ei: www.disney.com

www shows that it is a WWW server, the type of server created to deal with hipertext documents.

disney is, of course, the name of an organization.

The Top Level Domain is the last part of the domain where we can find a three letter suffix that indicates what type of page it is.

Ej: com = commercial
edu = educational
mil = military
gov = governmental
net = network
org = non-profit organizations

For countries other than the USA, a sufix is added which is a country code of two letters.

Ei: ar = Argentina
jp = Japan
ca = Canada
uk = United Kingdom

¿Would you like to see the full list of domains?

Note: With this two pieces of information, the location and type of server are defined. Usually these take you to a server's home page.

Path and Filename: these may or may not exist and they specify the names of the files, the connection port or the text to look for in the data base. Some access routes use special characters, numbers etc...

A complete URL could be the following:

http://www.servidor.com.ar/principal/bienvenido.html

http://www.server.co.uk/main/welcome.html

This web page whose protocol is http corresponds to a hipertext document welcome.html in the main folder/directory of the web server (www) called (.server) which is a commercial server (.co) in the United Kingdom (.uk)

Remember:

• A URL does not have spaces

• Un URL no tiene espacios.

• When in doubt always write a URL in small caps.

• If the URL we are using is not correct, the browser won't be able to access the page we wanted to visit.

Activity

1 - Connect to the WWW.

Remember that the browser automatically opens the predefined home page. You will see that the URL of the page is in the tool bar in the field Go to:...

In the previous guide we surfed through the Web but were limited to the links offered on the page. Now that we know URL's we can choose where to go if we know a websites address. This is done by writing the URL into the browser and it can be done in several ways.

A - by writing the full URL in the address bar and pressing ENTER.

B - Navigator: choosing File - Open Page. This opens the Open Page dialog box where we can specify the URL.

Explorer: choosing File - Open. This opens the Open dialog box where we can specify the URL.

C - by using one of the methods already metioned but only writing out the Partial URL instead of the complete URL.
This is everything that follows the protocol (http://, gopher://, ftp://) of the URL. (We cannot use for the protocols news: and mailto:)
On the address field we can also omit the www and the .com sufix in modern browsers.

D - by choosing Run from the Start menu, writing the URL or the partial URL and pressing ENTER. (It must include the www and the .com)

2 - Visit some of the following pages using the different methods. If you know other web pages you can also use them.

 

http://www.yahoo.com	http://www.lanacion.com.ar
http://www.netscape.com	http://www.filosofiapractica.com.ar
http://www.disney.com	http://www.cronista.com
http://www.clarin.com.ar	http://www.ibm.com
http://www.cdnow.com	http://www.greenpeace.org
http://www.tbeach.com	http://www.amnesty.org
http://www.elsitio.com	http://www.thehungersite.org

Don't be afraid of choosing links that interest you. Observe how the URL of each link changes. Many of them will be related to the original URL, but many won't have anything in common with it and might take us to the other side of the planet!

3 - Use the Back/Forward whenever you need them.

To return to the home page, we can click on the Home button and this will take us there.

 

Navigator:

Explorer:

The Print button prints the page shown on the screen.

 

Navigator:

Explorer:

4 - Choose a page you like and print it.

Remember to set the printer properties if you don't know what is preset on the machine you will use. You can also configure the browser's preferences to modify some printing parameters.

• Some browsers print background colors.

• Many web pages are long, so if you have legal size paper you will be able to print more on each page than if you print on A4 or letter size pages.

• You don't need to wait until printing has ended to continue surfing the Web.

Sometimes we want to interrupt data transfer. This transfer can be loading a website, downloading a file, a search, opening an image, video, sound, etc.. If we have made a mistake and don't want to wait until the page loads to then undo our mistake, or we changed our mind, or it takes too much time or for any other reason, to stop the transfer, we only need to click on the Stop button and the transfer will stop.

 

Navigator:

Explorer:

If we stop the transfer while a web page or it's media (images, sound, video, etc...) are loading, we don't let the browser load the rest of the page. The parts of the page that had been loaded before the Stop order will stay visible and we will be able to use it's links.

To load the complete page you need to click on the Reload/Refresh button.

 

Navigator:

Explorer:

5 - Load a web page, stop it and then choose Reload/Refresh.

The reasons to reload a web page can be:

• Once a page has been loaded, it is saved in our computer's memory (on the hard drive). The next time you access this same page, the browser will sometimes automatically go to the saved copy in order to save time (this can be changed in the settings). Meanwhile, the page might have changed. Some pages change very often, specially if they have news, sports results, business data, etc...

• Sometimes, a web page is not loaded completely, some of it's data is missing because the connection was interrupted, or because we ask the browser not to load the images or sound so that it takes less time to load. The browser can be preset not to show images, etc... unless we tell it to.

6 - The Back button returns us to the previous page you had visited. Try the following:

• Navigator: Keep pressing the mouse button until it displays a list with the last pages you have visited. In this way you'll be able to choose a specific site, if it appears. If it doesn't appear use the start button and go back to the home page.

• Explorer: Click the arrow next to the back button until it displays a list with the last pages you have visited. This way you'll be able to choose a specific site, if it appears. If it doesn't appear use the start button and go back to the home page.