| How the Web WorksBecause you're taking this | | | | the user, don't know the difference. A Web page is a |
| course and reading this lesson, it's a pretty safe | | | | Web page, no matter what kind of computer it lives |
| assumption that you can get on the Web and move | | | | on.A different kind of computers does not usually play |
| around with certain adeptness. To access any given | | | | well together and you know that most of the time it |
| web pages, we are most likely to use its web address | | | | takes a bit of jumping through hoops to make them |
| which is technically called a URL (Uniform Resource | | | | communicate. So why is it that the Web -- which is |
| Locator) and click on hyperlinks and graphics to move | | | | made up of all kinds of computers -- works so |
| from one page to another. In general, the Web is a | | | | seamlessly? It's simple, really. All of the clients and |
| pretty seamless world; you often move from one | | | | servers on the Web speak a common language called |
| Web site to another and may not know you have | | | | the HTTP protocol.Common GroundA protocol is a set |
| done so. If you want to add your Web page -- and | | | | of rules two computers use to communicate with one |
| eventually your Web site -- to this virtually seamless | | | | another. A protocol called HTTP (Hypertext Transfer |
| environment, you'll need to understand a bit about the | | | | Protocol) is spoken by both the Web browser and |
| workings behind the Web scenes.Of Clients and | | | | Web servers that carefully defines how Web pages |
| Servers | | | | are requested and received. It doesn't really matter |
| Simply put, the Web is a gigantic network. What that | | | | which operating system is running for as long as both |
| means in geek-speak is that there are, in the most | | | | the browser and the server speak HTTP. The HTTP |
| general terms, two roles that a computer can play on | | | | protocol is the common ground that allows them to |
| the Web: client or server. Anything else deliverable | | | | communicate.Different computers just could not work |
| over the Web including documents, images, sound files | | | | with each other and so without protocols, the web |
| is stored by the server and clients access those files. | | | | would not work at all. Although HTTP is the protocol |
| Occasionally, a computer can play both roles, but more | | | | for requesting and sending Web, there are other |
| often than not, a computer is one or the other.For | | | | protocols as well at work on the Internet besides |
| example, when you type the URL into your Web | | | | HTTP.Putting It All TogetherThe HTTP protocol is |
| browser, your client is sending a request to the Yahoo | | | | written in HTML (Hypertext Markup Language) to |
| Web server -- ( identified as for a Web page called | | | | request and send the actual web pages that clients |
| home.html. When the Web server receives your | | | | and servers uses.A Large amount of data can be |
| request for home.html, it looks to see if the Web page | | | | stored on the server and the same serves if to |
| exists, and if it does, the server sends a copy to you | | | | hundreds of clients, often at the same time. A |
| so that you can view it in your browser. An error | | | | collection of web servers is actually what is used to |
| message is received to let you know that the page | | | | respond to client request by web sites like Yahoo and |
| you wanted could not be found whenever the page | | | | Microsoft as they receive hundreds of thousands of |
| does not exist on the server. Web Clients and could | | | | hits everyday. It is not mandatory for the Web server |
| Web Servers communicate with one another through | | | | to run the same kind of operating system which the |
| a system of requests and responses.The Web would | | | | Web clients is using whenever the Web pages are |
| not work without clients and servers. The clients could | | | | being requested. Protocols fill the communications gap |
| access each of the web documents stored on the | | | | between different kinds of computers and allow them |
| servers all over the world regardless of where the | | | | to exchange Web pages simultaneously.What This |
| client or server is actually located. This means you can | | | | Means To YouYou may be wondering why you |
| request pages from servers in Sydney, Australia, and | | | | should care about what goes on behind the scenes of |
| Van Horn, Texas in the exact same way and receive | | | | the Web. In fact the web is designed in such a way |
| responses from each server in the exact same way. | | | | that you don't need to care as a web surfer. To find a |
| In the end, Web surfing is nothing more than a Web | | | | place to serve your web pages needs to be found by |
| client -- a.k.a. A series of web pages are being | | | | you as a web developer -- a Web server of some |
| requested from the Web servers located all around by | | | | kind -- so that your users can request your pages |
| the Web Browser.How Protocols Help Computers | | | | using their Web browsers. Your Web pages can't be |
| CommunicateAll kinds of operating systems -- PCs, | | | | seen by the world unless they reside on a Web |
| Macs and Unix to name just three -- is running all | | | | server that is hooked up to the Internet. Anyone with a |
| across the world and both clients and servers can be | | | | Web client could access your web pages, once your |
| any kind of computer running any kind of operating | | | | pages are made available to a connected |
| system. You could be using a computer which is | | | | server(remember, that's a fancy name for a browser). |
| running on windows to serve you with a website and | | | | For now, that's all you need to know about Web |
| likewise one may surf the web with a Macintosh client. | | | | clients and servers. In a later lesson you'll learn more |
| A Unix computer running Linux may serve the next | | | | about finding a Web server home for your documents. |
| Web page you view. The beauty of it all is that you, | | | | |