5 How the web actually works

In this day and age it's good to have a thorough understanding about what happens when you follow a link on a web page or send by hand a URL to a web server.

Let's suppose that you want to see what a certain web page on the Net has to show. In order to accomplish this you must follow a certain procedure:

1    Firstly you must start your web browser and have a connection to
the Internet (Note that the connection can also be wireless).

2    Then you'll give a browser the URL of the document. You can also click a hyperlink which passes the URL behind the link to the browser.

3    The document you want to see is not on the disk of your own computer but somewhere else in the world. So, the browser can't read the document in the same way it reads files stored on the disk of your own computer. Instead, the browser sends a request to the computer where the web page is stored. That request specifies which document is wanted.

4    The computer that contains the web page you want to see constantly runs a program that is generally called a web server. That program's job is to listen to requests from browsers and then perform the service asked.

5    The web server receives the request, studies it and, if possible, retrieves

       the desired document.

6    When the document is retrieved or finished, the web server sends a response to the browser. That response also contains the document as one part of it.

7    The browser in your own machine receives the response from the server, takes the document part out of it and displays the document to you on your screen.

8    When you want to follow another link and click on it, the whole procedure starts again.

Note that there's never a direct physical connection between the computer on which the browser features and a server machine. A browser and a web server are only programs sending messages to each other. 

It's usual to visualize things in the following way: the machine where a browser is used and the computer where a web server is running can be located, for instance, in one single company building. And the pages to be displayed in the browser don't need to have anything to do with the outside world. The web pages can belong to some application made just for that enterprise or organization.

In other words, the same techniques that are applied when dealing with the World Wide Web can be used for a single organization in applications customized just for that organization itself. Indeed this is becoming more and more common. So, the net technology itself is very widely used today and will be used even more in the future. That's one of the reasons why it's good to get acquainted with the programs called browsers.