HTTP is a communication standard governing the requests and responses that take place between the browser running on the end user's computer and the Web server. The server's job is to accept a request from the client and attempt to reply to it in a meaningful way, usually by serving up a requested web page - that's why the term server is used. The natural counterpart to a server is a client, so that term is applied both to the web browser and the computer on which it's running. All this and more is explained in this first chapter.