Không có vấn đề gì bạn làm trên web, đó là tất cả về yêu cầu và phản ứng. Một yêu cầu web được gửi từ một trình duyệt web đến một máy chủ web như là kết quả của một số tương tác người dùng. Trên máy chủ web, một phản ứng web (hoặc trả lời) được xây dựng và gửi trở lại cho trình duyệt web. Toàn bộ quá trình có thể được tóm tắt trong năm bước. | web development You can put your program on the Web A webapp is what you want. If you develop your program as a Web-based application or webapp for short your program is Available to everyone who can get to your website In one place on your web server Easy to upate as new functionality is needed do webapps actually work you are here 4 215 anatomy of a web request Webapps Up Close ----------------------------------------------------------------------- No matter what you do on the Web it s all about requests and responses. A web request is sent from a web browser to a web server as the result of some user interaction. On the web server a web response or reply is formulated and sent back to the web browser. The entire process can Step 2 The web browser converts the user s action into a web request and sends it to a server over the Internet. be summarized in five steps. Deciding what to do next One of two things happen at this point. If the web request is for static content such as an HTML file image or anything else stored on the web server s hard disk the web server locates the resource and returns it to the web browser as a web response. If the request is for dynamic content that is content that must be generated the web server runs a program to produce the web response. Step 3 The web server receives the web request and has to decide what to do next. Step 1 Your user enters a web address selects a hyperlink or clicks a button in her chosen web browser I just type the web address into my browser s location bar and press Enter. tieve to Hey hello this A web request just for me How nice. Server 216 Chapter 7 web development Step 4 The web server processes the web request creating a web response which is sent back over the Internet to the waiting web browser. Server Step 5 The web browser receives the web response and displays it on your user s screen. a Here you web response generated just for you. Enjoy The potentially many substeps of step 4
