University of Malta  WWW WORKSHOP 

SESSION 1
INTRODUCTION TO INTERNET

Contents

What the Web is

The Web, for want of a better term (it is also known as "the World Wide Web, the Internet, the Net etc.) can be thought of as a large, geographically distributed collection of computer networks -- a network of networks.

There is nothing very new about networks. What makes the Internet unique is

This commmon framework allows any computer on any network to communicate with any other, despite wide differences in their physical makeup and internal organisation.

The language shared by computers on the Web is, by human standards, pretty simplistic and is in fact little more than a set of conventions that define how to exchange and interpret data in certain, predetermined formats. The set of linguistic and behavioural conventions for a particular job is called a protocol, and typically, computers attached to the web can handle several different protocols.

Examples of Protocols

Two of most important standards (protocols) used on the web today are HTTP and HTML. Let's look at each of those protocols more in depth For instance, there is one for organising the browsing of hypertext documents, another for electronic mail messages, another for file transfer etc.

Browsing

If you have got as far as reading this page, you have probably found out that browsing the Internet resembles browsing in a library or a bookshop, involving not only the contents of books (cf. web pages), but also with references to books (cf. links) and contexts (cf. websites) in which books are to be found.

Browsing on the Internet is carried out using a browser on your computer. The best-known examples of browsers are Netscape and Microsoft Explorer, both of which are available at no cost. For this course we will use Netscape and you are strongly advised to install it on the computer that you will use to follow the course. See the next section for instructions on how to download Netscape at no cost.

URLs

In order to be useful, the browser needs to be told what to browse. This is achieved by means of a URL (or Uniform Resource Locator) which is a unique name for any browsable item on the internet. URLs have a particular format, illustrated by the following example which happens to be the home page of this course:
http://www.cs.um.edu.mt/~mros/wwww/index.html

Notice that it consists of several different parts as shown below

protocol separator server name domain file-directory file-name
http: // staff .cs.um.edu.mt /mros1/wwww/ index.html

In this case, the protocol is http: which is used for browsing normal hypertext pages. N.B. Most servers allow the filename to be omitted. In such cases, a standard filename (usually "index.html" or "default.html") is automatically assumed.

Other common protocols appearing in URLs are mailto:, ftp:, and file:.

mailto:
This is used to create a mail message to a specified recipient. By clicking on mailto:mros1@um.edu.mt, for example, you will send me a message. Notice the absence of "//" separators in this kind of URL.
ftp:
FTP stands for file transfer protocol. This is used for transferring files either from your computer to a server (uploading) or from a server to your computer (downloading). Typically, when downloading, you will be asked for the name of a file in which the downloaded file will be stored. However, if the file is a plain text file, it may simply be displayed. The exact behaviour depends on the way your browser has been set up.
file:
The file: protocol is not really a protocol at all in that it specifies a file stored on a machine. Although of limited use in a networked environment it is handy for accessing personal files on the home computer where the browser is running. As such, it can be used for browsing and editing "personal" document collections that are not yet published on the Internet.

Visiting URLs

To visit a URL, make it appear in the ``location" box appearing in the toolbar above the window, either by typing explicitly, or by cutting and pasting. To get back use the back button. Another way to browse the same object is to click on a link to the same object, getting back once again by using the back button. If you need to download netscape, you can it from here.

Saving Links Using Bookmarks

Very often we visit an object and for some reason wish to return to it later on. One way to do this is first remember the address, retype it in the location box, and then go to it. An easier way is to make use of the bookmarks facility.
  1. Click the bookmarks icon
  2. Select "Add Bookmark"
  3. Release
The link is now saved. To revisit it, repeat the above procedure but instead of selecting "Add Bookmark", select the saved link by scrolling down the list.

Exercise 1.1

Point your browser at the following URLs and bookmark them:

Editing Bookmarks

When your collection of bookmarks reaches a certain size, it becomes difficult to manage. Netscape Communicator provides facilites for organising collections of bookmarks into hierarchical directories. The main features are (a) editing bookmarks (b) creating new folders (c) moving bookmarks into folders.

To see the built-in directory structure carry out the following steps.

  1. Click the bookmark icon
  2. Select "edit bookmarks"
  3. Resize the window to suit your needs
  4. Near the top of the window find the title bar ("location", "name" etc.).
  5. Adjust the width of the columns to suit your needs by dragging the vertical field dividers to suit your needs.

To edit an individual bookmark

  1. Select the bookmark
  2. Go to the edit menu
  3. Select "bookmark properties"
  4. Edit to suit your needs
  5. Click "OK" or "cancel"

To create a new folder

  1. Go the file menu
  2. Select "new folder"
  3. Edit according to your taste
  4. Click "OK" or "cancel"
  5. If the folder is not where you want it, select it, drag to the desired location, and release.
Note that it is possible to put a folder "within" or "next to" another folder: it all depends on what structure you want to create.

To move a bookmark into a folder there are several possibilities. The easiest is to select the bookmark, drag it to the folder, and release. This isn't always easy or possible. In cases of difficulty:

  1. Select the bookmark
  2. Got to the edit menu and cut it
  3. Move the cursor to the desired desitination
  4. Go back to the edit menu and select "paste".

Exercise 1.2

Organise the bookmarks you created in the last exercise using the above techniques.

Searching

Very often you will not know the URL that is relevant to the information you are seeking. Luckily the Web offers a number of excellent services to help you find out. Some of the best-known "search engines" are Infoseek, Excite, Lycos, Alta Vista, and Webcrawler, all of which can be accessed using the search button.

For the most part, the usage of the different engines is self explanatory. For those who need it. Further information on specific search engines is available on this site.

Creating a First Web Page

Web pages are written in a special mark up language called HTML (Hypertext Markup Language). You can always view the HTML corresponding to the page you are looking at by going to the "view" menu and selecting "page source".

Exercise 1.3

Look at the page source for the current page. To get back to the present page, close the source page window.

Composer

At this stage, it is not necessary to be familiar with HTML to create your own web pages, since Netscape provides an HTML editor called "Composer" within the Communicator package. Composer is a WYSIWIG editor, which means that you operate with a displayed page that looks very much like an ordinary web page, unlike the source code seen above.

To access Composer

  1. Go to the file menu and select "new"
  2. Select "blank page"
  3. You can now edit the page in a very similar way to an ordinary word-processing style editor.

Exercise 1.4

  1. The aim of this exercise is to create an extremely simple home page for yourself, based on this model, using Composer.
  2. Try to copy both the style and also the layout, using what you think are the right tools. If you make a big mistake, you can always undo using the "undo" menu.
  3. When you are finished, write the file, selecting "write as" in the "file" menu. Make sure the file has a ".html" suffix, placing it on to your local disk (e.g. in the directory "My Documents")
  4. Now open the file using the browser: go to the "file" menu,
  5. Select "open page" and then "choose file".
  6. You now have a choice between Navigator (the browser) or Composer (the editor). You may at this stage wish to to some more editing. If not, choose the browser

Course Home CSC Home Resources Session 2
Mike Rosner (mros@cs.um.edu.mt)
[Wed Jan 26 17:23:44 2000]