| Basic CGI and Perl scripts have been used since the beginnings of the Web, but CGI is being superseded by application servers. Application servers, such as ASP, JSP, ColdFusion, and PHP (also known as middleware), have overcome some of the performance problems associated with CGI. They are also written in languages that are easier to understand for HTML developers (in the case of ColdFusion) or for Windows programmers (in the case of ASP). Almost anything you can do with CGI you can also do using an application server. Many Web servers have the application server built in, or the application server is easily installed, making the Web server simpler to administer than the early Unix machines. You can think of application servers as CGI scripts with bells on. Most of the processes described here for CGI apply to application servers, and the principles are the same. Finally, and important for us, Dreamweaver MX provides much better support for application servers than for CGI scripts. But the strength of CGI is its ubiquity. Every Web server runs CGI, no matter how old it is. If you have investigated getting your Web site hosted, you'll know you usually have to pay a lot more to get ASP or ColdFusion from your ISP. Yet even free Web hosting gives you access to a few useful CGI scripts. Because CGI has been around so long, and runs on so many servers, you can usually find a CGI script to do almost anything you want and it will often be free. |
