CGI – Common Gateway Interface: not a language but a standard protocol developed to allow web pages to send information to each other. It defines the syntax used by arguments and environment variables passed on by web pages – typically those collected by forms – so that the pages at the receiving end know what to expect. The programs which actually process these variables may be written in any of the languages below:
Perl – no acronym, just a variation of ‘Pearl’. Developed by Larry Wall in 1987 and developed extensively since, Perl is a high-level general-purpose interpreted programming language originally developed for producing complex reports, but now rarely used outside the Web. Perl has a strong core of support but is less widely used now that more specifically web-focused languages like PHP and ASP have become popular. Its very flexibility, with the inclusion of non-standard features like list handling, make it fairly intimidating for novices.
PHP and ASP
PHP – recursive acronym for PHP Hypertext Processor. PHP is an open-source interpreted server-side language; that is, it requires the web host to have PHP handling installed on the ‘back end’ of the site. This is fairly common, however, especially among paid hosts. PHP syntax is scary, with a liberal use of dollar signs, question marks, brackets, semicolons and other punctuation characters, but once this is mastered the language itself is not too difficult. PHP normally runs on web pages given a .php extension, where it may appear in functional blocks or be interspersed through HTML code in the body of the page. PHP applications tend to be constructed out of many small interlinked files, each with a specific purpose. Many free blogging and content-management systems such as Joomla! and Drupal are written in PHP.
ASP and ASP.NET. ASP (Active Server Pages) is Microsoft’s answer to PHP – a server-side interpreter designed for web form handling and database management. The syntax is equally forbidding, and in order to run ASP a web host must pay a licence fee to Microsoft, which makes ASP servers rarer and more expensive than their PHP equivalents. ASP.NET is a compiled version of the language released as part of Microsoft’s move to a global ‘.NET framework’.
Java and C
Java – once the great white hope of the Internet, Java is a complex object-oriented compiled language used to produce functional chunks of binary code called ‘applets’ which can be embedded in web pages. Originally appearing in 1995, Java was widely hyped as a platform-neutral system which would allow programs to run in a range of environments without modification, but its slow performance and user-unfriendly syntax disappointed many would-be users, and much of its audience was stolen by friendlier programming environments like Macromedia (now Adobe) Flash. Recent improvements in speed and programmer-friendliness may see Java re-emerge as a contender.
That ought to keep you busy for a while, anyway…