菜单
  

    The server produced static pages for the client browser, which would simply interpret and display them. Basic HTML contains simple mechanisms for data gathering: text-entry boxes, check boxes, radio boxes, lists and drop-down 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 common action is to run a program located on the server in a directory that’s typically called “cgi-bin.” (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 “cgi-bin” within all the gobbledygook there.) These programs can be written in most languages. Perl is a common 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 become overly complicated 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 Internet. (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 client-side 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. Client-side 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 client-side 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 client-side programming. The rest of this section provides an overview of the issues and approaches in client-side programming.

  1. 上一篇:LED前照灯的设计英文文献和中文翻译
  2. 下一篇:高校计算机辅助教学英文文献和中文翻译
  1. 汽车乘员舱的声振耦合英文文献和中文翻译

  2. 立体光照成型的注塑模具...

  3. 数控机床英文文献和中文翻译

  4. 工业机械手英文文献和中文翻译

  5. 低频振动的铁路车轴的状...

  6. 接头的形状对沥青塞接头...

  7. 数控加工技术英文文献和中文翻译

  8. 十二层带中心支撑钢结构...

  9. 酸性水汽提装置总汽提塔设计+CAD图纸

  10. 杂拟谷盗体内共生菌沃尔...

  11. java+mysql车辆管理系统的设计+源代码

  12. 当代大学生慈善意识研究+文献综述

  13. 乳业同业并购式全产业链...

  14. 中考体育项目与体育教学合理结合的研究

  15. 大众媒体对公共政策制定的影响

  16. 河岸冲刷和泥沙淤积的监测国内外研究现状

  17. 电站锅炉暖风器设计任务书

  

About

751论文网手机版...

主页:http://www.751com.cn

关闭返回