Web Browsing

Every document on the internet has its own unique address. These addresses are called URL's (for Uniform Resource Locator). To access any document you must know the URL for that document.

To get to the location of a document on the internet the HyperText Transport Protocol (http) is used. Addresses, therefore, typically start with http:// and then give the unique URL for the document that is to be accessed. For example, the URL for Rivier College is http://www.rivier.edu and the URL for the document you are now viewing is http://www.rivier.edu/faculty/dburgess/web/ic/browsing.htm. (See the Location box at the top of the screen.) The name directly following the http:// gives an indication of the type of organization that you will be connecting to. Some common endings for that name are edu (education), gov (government), com (commercial), org (organization), etc. Rivier College is, of course, an educational institution and has edu at the end of its name.

Finding the URL of a particular document can be tricky. Search engines have been created to help find documents. Each search engine has strengths and weaknesses. A list of search engines is locally available to evaluate the relative usefullness of these search tools.

A browser is needed to see the document. Some of the more familiar browsers are Netscape Navigator, Internet Explorer, and Lynx. These browsers make sense of the code that is embedded in a web document and display the document on the computer screen.

In the past Netscape browsers were the most widely used browsers, but Microsoft Internet Explorer is now bundled with almost every new computer and so it is the most widely used today. Along the top of these browsers are a number of buttons that are shortcuts to different functions that are useful when browsing the web. For example:

• Back - takes you back to the previous URL location.
• Forward - takes you forward (only active after using Back).
• Reload/Refresh - reloads the current URL (useful when editing pages).
• Home - takes you to the startup URL.
• Search - takes you to the Microsoft search engines page.
• Print - prints the current page or active frame.
• Stop - stops loading a requested URL.

Lynx is a text-only browser and uses keyboard input to access similar functions. In lynx, for example, typing g (for go) will allow you to open a URL.

Web pages often have connections to other web pages. These links are usually identified by an underline and, for graphical browsers, by a specific color. In this page links that have not been accessed are blue and links that have been accessed are red. Notice that the words in the last sentence are not underlined and are not links to other pages. Here is a link to the FBI that you have probably not gone to. It should be blue. Here is a link to this page that was previously accessed and should be red. Go to the FBI and then use the Back button at the top of the page to come back. The FBI link should go red. The colors for links can be set in the document and may be different from page to page. It is better, however, to leave the links with the default color since everyone automatically looks for those colors and identifies them as links.

You may want to be able to get back to a particular page quickly. The location of a page can be saved into a Bookmark (Netscape) or Favorites (Explorer) list and readily accessed later. These are found at the top of the page. Click on Bookmark (or Favorites) and then click on Add Bookmark (or Add Favorites) and the location will automatically be saved. If you want to go to that page again, click on Bookmarks (or Favorites) and then click on the name of the page in the list that you want to go to.

Web pages are written using HyperText Markup Language (HTML) and regular English. HTML gives directions to the browser as to how the page should look, how to connect to other pages, and other aspects of the web page. It is not necessary to know HTML to use the World Wide Web. The browser takes care of all of the details. Documents that are written in HTML usually have .html or .htm at the end of the file name. Either html or htm is acceptable. This file, for instance, is named browsing.htm and the previous page is named index.html.

Web pages that are grouped together constitute a web site. A web site generally has an initial page that allows navigation through the site. The initial page is called the homepage. The page previous to this one is the homepage for Internet Communications. This page is a page within the web site for this class, but is not a homepage. Notice that the Internet Communications homepage is only one page in the Rivier College web site which has its own homepage. It is important to designate the scope of the homepage. Rivier College, the Chemistry Department, the General Chemistry class, Dr. Burgess and a host of other departments, classes, and people all have homepages within the Rivier College web site. Notice that the URL for all documents at the Rivier College site will begin with http://www.rivier.edu (recall that this page is http://www.rivier.edu/faculty/dburgess/web/ic/browsing.htm).

The name of the host site for Rivier College is www.rivier.edu. The location of specific web pages in that site has to be uniquely specified. The words after the name of the host site designate a unique path to a document. This page (see the URL given above), browsing.htm, is in the ic directory, which is in the web directory, which is in the dburgess directory, which is in the faculty directory at Rivier College. It is kind of like the telephone book. If your name is Don Smith, you could be found in the Smiths, under s, in the white pages, of the phone book. The path could be written as phone_book/white_pages/s/smith/don.

Computers that store and allow access to the documents of a web site are called web servers. Computers that access web documents are called clients. The computer you are using is currently a client of the Rivier College web server (called www.rivier.edu).

Connections to web servers can be made directly if your computer is part of a local area network (LAN) or it can be made through a modem from a computer that is not directly connected to the LAN.

Activities for while you are waiting to get further instuctions:

1. Take the quiz covering this material.
2. Do the exercises in Tutorial 4 of your text.
3. In class exercises (not up to date!).