【正文】 外文翻譯 學(xué) 院： 計(jì)算機(jī)與信息工程學(xué)院 專 業(yè)、 班 級(jí)： 信息管理與信息系統(tǒng) 學(xué) 號(hào)： 姓 名 ： Java and the Inter If Java is, in fact, yet another puter programming language, you may question why it is so important and why it is being promoted as a revolutionary step in puter programming. The answer isn’t immediately obvious if you’re ing from a traditional programming perspective. Although Java is very useful for solving traditional standalone programming problems, it is also important because it will solve programming problems on the World Wide Web. 1. Clientside programming The Web’s initial serverbrowser design provided for interactive content, but the interactivity was pletely provided by the server. The server produced static pages for the client browser, which would simply interpret and display them. Basic HTML contains simple mechanisms for data gathering: textentry boxes, check boxes, radio boxes, lists and dropdown lists, as well as a button that can only be programmed to reset the data on the form or “submit” the data on the form back to the server. This submission passes through the Common Gateway Interface (CGI) provided on all Web servers. The text within the submission tells CGI what to do with it. The most mon action is to run a program located on the server in a directory that’s typically called “cgibin.” (If you watch the address window at the top of your browser when you push a button on a Web page, you can sometimes see “cgibin” within all the gobbledygook there.) These programs can be written in most languages. Perl is a mon choice because it is designed for text manipulation and is interpreted, so it can be installed on any server regardless of processor or operating system. Many powerful Web sites today are built strictly on CGI, and you can in fact do nearly anything with it. However, Web sites built on CGI programs can rapidly bee overly plicated to maintain, and there is also the problem of response time. The response of a CGI program depends on how much data must be sent, as well as the load on both the server and the Inter. (On top of this, starting a CGI program tends to be slow.) The initial designers of the Web did not foresee how rapidly this bandwidth would be exhausted for the kinds of applications people developed. For example, any sort of dynamic graphing is nearly impossible to perform with consistency because a GIF file must be created and moved from the server to the client for each version of the graph. And you’ve no doubt had direct experience with something as simple as validating the data on an input form. You press the submit button on a page。 the data is shipped back to the server。 the server starts a CGI program that discovers an error, formats an HTML page informing you of the error, and then sends the page back to you。 you must then back up a page and try again. Not only is this slow, it’s inelegant. The solution is clientside programming. Most machines that run Web browsers are powerful engines capable of doing vast work, and with the original static HTML approach they are sitting there, just idly waiting for the server to dish up the next page. Clientside programming means that the Web browser is harnessed to do whatever work it can, and the result for the user is a much speedier and more interactive experience at your Web site. The problem with discussions of clientside programming is that they aren’t very different from discussions of programming in general. The parameters are almost the same, but the platform is different: a Web browser is like a limited operating system. In the end, you must still program, and this accounts for the dizzying array of problems and solutions produced by clientside programming. The rest of this section provides an overview of the issues and approaches in clientside programming. One of the most significant steps forward in clientside programming is the development of the pl