Working of Web
Usually people think that Internet and the web is, alike. Actually, the Internet is merely an international network of computers and the web runs on top of the Internet, and makes it useful for everyone. How do the webs work?
How was the web invented?
The web was invented 20 years after the start of the Internet. Tim Berners-Lee invented web in 1989. At that point, people had been trying to work out effective ways of sending information around on the Internet. Email was invented in 1971, but there was no system at that time, that could really exploit the net’s potential.
Everything changed with the invention of the web. Berners-Lee’s big inspiration was to apply the idea of links to the Internet: the web was possibly a mass of pages that one could move amid by clicking on links. Format for these pages (HTML), and writing of the first web browser to view them with, as well as the first web server for sending them to other people’s web browsers was all invented by him.
Links were revolutionary at that time though they do not seem much now. Internet access would be useless without the web. As one cannot imagine what the web would be like if one had to keep typing long addresses every time he/she wanted to move from one page to the next, or using long numbered menu systems that work differently from one site to the next.
Browsers and Servers
One is using the web when one is using any web browser like Internet Explorer or Mozilla Firefox or any other web browser. As these web browsers, works like-
1. When one opens his/her web browser, it goes to his/her home page. He/she can click links to other websites, or to other parts of the same website. One can type in a search and click links in the search results if his/her home page is a search engine. One can type in the address of a site if he/she knows the site address and then to keep going, click on more links from there.
2. A browser looks at two things each time one clicks a link: the name of the web server it links to, and the name of the page it links to on that server. Now let me explain this with an example by using HTTP (Hypertext Transfer Protocol) the address ‘http://www.sample.com/newpage.html’ tells the web browser to get the page called newpage.html from the server at www.sample.com. Connected to the Internet, this server is a real computer that has the page one wants to read stored on its hard disk.
3. Using DNS (Domain Name System), web browser looks up & finds out where this server is, which turns the text address into a number. This IP (Internet Protocol) address looks like a phone number consisting of four numbers between 0 and 255. Once one knows its IP address, it can easily find the quickest route from his/her ISP (Internet Service Provider) to the server, and start communication. The Internet is set up to make it easy to find a server anywhere in the world. This entire procedure, from DNS lookup to connection, will repeatedly take much less than a second.
4. Web server takes action by sending back the HTML (Hypertext Markup Language) code for that page, once the web browser sends an HTTP request to that web server. Web browser turns this code into a page that one can analyze. One can click more links, from there to start the process over again.
One can now use the web to download anything, from pictures to programs, but it all works in the same way. Of course, all this has become quite easy: modern browsers and servers send around much more than HTML code.
One will get an error if something goes wrong somewhere in this process like ‘the page cannot be displayed’, this error means that the server’s name was wrong, or that it doesn’t have the page he/she wants. One might often see errors like “the server is currently too busy with other people’s requests to respond,” or that “the page you wanted has moved.” The best thing to do in each case is to follow the instructions on the error page, which usually means checking the address and trying again.