Tham khảo tài liệu 'web client programming with perl-chapter 2: demystifying the browser-p1', công nghệ thông tin, quản trị web phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 2 Demystifying the Browser-P1 Before you start writing your own web programs you have to become comfortable with the fact that your web browser is just another client. Lots of complex things are happening user interface processing network communication operating system interaction and HTML graphics rendering. But all of that is gravy without actually negotiating with web servers and retrieving documents via HTTP the browser would be as useless as a TV without a tuner. HTTP may sound intimidating but it isn t as bad as you might think. Like most other Internet protocols HTTP is text-based. If you were to look at the communication between your web browser and a web server you would see text--and lots of it. After a few minutes of sifting through it all you d find out that HTTP isn t too hard to read. By the end of this chapter you ll be able to read HTTP and have a fairly good idea of what s going on during typical everyday transactions over the Web. The best way to understand how HTTP works is to see it in action. You actually see it in action every day with every click of a hyperlink--it s just that the gory details are hidden from you. In this chapter you ll see some common web transactions retrieving a page submitting a form and publishing a web page. In each example the HTTP for each transaction is printed as well. From there you ll be able to analyze and understand how your actions with the browser are translated into HTTP. You ll learn a little bit about how HTTP is spoken between a web client and server. After you ve seen bits and pieces of HTTP in this chapter Chapter 3 Learning HTTP introduces HTTP in a more thorough manner. In Chapter 3 you ll see all the different ways that a client can request something and all the ways a server can reply. In the end you ll get a feel for what is possible under HTTP. Behind the Scenes of a Simple Document Let s begin by visiting a hypothetical web server at http . Its imaginary and .
