1. Browsers

A "Browser" is a computer program which, with the correct Internet connection, will allow you to view formatted text and graphics on the Internet.

You are using one right now to view this course. It is probably some version of Netscape, Netscape Communicator or Microsoft Internet Explorer (IE).

Basically, a "browser" in computereze is an "interpeter." That is, it takes a page of ordinary text (ascii text) in which are embedded HTML formatting commands and "intreprets" those commands so that the page of text appears in a window as the author wishes it to appear. Such commands might be to make a title bold, or put the name of a book in italics. (Browsers today are also JavaScript interpreters, but that is beyond the scope of this course.)

In this course you are going to learn (among other things) how to embed those "formatting" commands into a page of text so that the page will appear in a browser as you would like it to appear.

The two browsers mentioned -Netscape and Internet Explorer, the top of whose windows appear below- are quite similar, but unfortunately do not always use the same words for the same things.

Netscape Header Graphic
The top of Netscape: Version 4.5
IE Header Graphic
The top of Internet Explorer: Version 4.0

Looking at the two graphics above, you can see that some of the same things appear on the top of both of the browser windows but not all. For example, Netscape has a "Print" button while in Internet Explorer you use the "Print" choice on the "File" menu. Also, to reload the page into the browser window on Netscape, you click on the button "Reload." In IE you click on the button "Refresh." The place where you put the URL (Universal Resource Code, which is the "address" of the web page you are viewing) is called "Location" in Netscape and "Address" in IE.

Web Addresses or URLs

Now is probably a good time to mention the address, known as a URL, of a web page. Each web site runs a program called a "web server." This web server has a name, a domain name, and uses directories on that computer to store web pages.

When you ask your browser to show you a web page, you type a URL in the "Location" or "Address" blank in the browser. That tells the browser to use the "hypertext transfer protocol" or "http" on the Internet to locate the server, which will have a name like "newton," or "www," and a "domain" name like "uor.edu" or "esri.com."

Besides the name and domain of the server, you need to specify where in the host computer's directories the page you are seeking lies. That is accomplished by using the back slash, "/", after the domain and then again between each directory until you come to the file you want. That HTML file will have a name with the extension ".html" or ".htm". The example below shows the correct form for a URL to access the page "Baty.html" on the server "newton" in the domain "uor.edu".

http://newton.uor.edu/FacultyFolder/Baty/Baty.html

What you see above is called a "link" and if you click on it, it will use "http" (hypertext transfer protocol) to locate and connect to the computer named "newton" in the domain "uor.edu." Then it will take you to the web page named "Baty.html" which is in the subdirectory "Baty" of the directory "FacultyFolder".

Try this now. After viewing it, use the BACK button on the browser to return to this page.

Domain names are always the last two "xxx.xxx" before the first "/". Everything from the "http://" to the domain name is the name of the server. Everything from the first "/" on is the directory pathway to the HTML file.

Using this formula on the URL above, the domain is "uor.edu," the server's name is "newton," and the pathway to the file on the server is "FacultyFolder/Baty/Baty.html."

Caution

While HTML is intepreted in the browser on your computer, the URL has to match the requirments for directory and file names of the computer on which the server resides. That means that you need to be very careful of the case (upper or lower) of all the letters in the names of directories and the names of the files. Servers on machines running the UNIX operating system are particularly picky about case. Since you won't know what operating system is running on the computer you are connecting to, you need always to check on the case of the letters in the directory names and the files when you get an error.

To show what that means, below is essentially the same link as above, but the two "Fs" in FacultyFolder are written lower case. When you click on it, you will get an error message from newton. It won't be able to tell you what the error is, but will give you some options. Try it, and use the BACK button to return here.

http://newton.uor.edu/facultyfolder/Baty/Baty.html

Newton, our campus webserver, uses IBM's AIX as its operating system. That is IBM's version of UNIX, and it sees upper and lower case letters as completely different letters. That means that you may have a file named "Baty.html" and another named "baty.html" in the same directory on the computer with no name conflict. Sometimes UNIX has advantages and sometimes it just causes problems.

Usually after using browsers for a while, you become familiar with the various operations and will recognize the "process" by some name no matter which browser you have to use.

Exercises 1

Select (by dragging the mouse across it with the button held down) the entire URL currently in the "location" or "address" space in your browser. With it selected type the text below exactly as written.

http://www.redlands.edu/about/DIRCT.HTM

After typing it you need only to press the RETURN or ENTER keys on the keyboard to have your browser attempt to open the page. READ THE FOLLOWING PARAGRAPH BEFORE YOU TRY TO DO THAT.

You should arrive at a page on the "official" University of Redlands web server. If it gives you an error, it means that things have been moved since this was written (Always a hazard when you are using the Web.), or you have typed the URL incorrectly or the server is not functioning. Don't worry, that will not affect the exercise. Use the BACK button to return to this page. Open a text editor or word processor on this computer and type into it the answers to the following questions.

  1. What is the name of the server (computer) on which the HTML page you are trying to access is stored?
  2. What is the "domain" of the server?
  3. What is the name of the HTML file?
  4. In which directory on the server is the file located?
  5. Change the word "about" in the URL to "ABOUT." Does it brings up the web page?
    1. If it does, what do you probabably know about the server's operating system?
    2. If it doesn't, what do you probably know about the server's operating system?
The standard domain designations in the USA are xxx.edu, xxxx.com, xxxx.org, xxxx.gov, and xxxx.mil standing respectively for educational institution, commercial business, professional organization, US government, and US Military. In other countries the domains end with a two letter country code rather than those above. You can find all those country codes by going to

http://www.cyberenet.net/~rhackenb/international.html

This is a link, so all you have to do is click on it to go there. Remember to use the BACK and FORWARD buttons to jump back and forth between that page and this one.

With that information, in your word processor or text editor, answer all the following questions about the site you get to when you put the following the "location" or "address" in the browser.

http://homebrew.cs.ubc.ca/webct/intro/usertypes.html
  1. What country is the home of this web server?
  2. Can you determine anything else about its specific location from what is on the page when it loads?
  3. What is the name of the server (computer) on which this HTML page is stored?
  4. What is the "domain" of the server?
  5. What is the name of the HTML file?
  6. In which directory on the server is the file located?
  7. What directory is it a subdirectory of?
  8. Change the word "intro" in the URL to "INTRO". Does it still bring up the web page.?
    1. If it does, what do you probabably know about the server's operating system?
    2. If it doesn't, what do you probably know about the server's operating system?

OK, that is the last of the questions. Save your document as Exercises_1 and print them out so you have a record of what you did.

If you want to see my answers, click here.

After reading the answers, to put things back the way they were, use the BACK button or scroll down to the link at the bottom of the page of answers.