PHP is a recursive acronym for PHP Hypertext Processor. Unlike the other offerings listed, PHP is designed specifically for server-side programming, which means that its library is specialized for the tasks you'll be doing over and over again in the course of programming your website. PHP also has the advantage of being able to interweave code with HTML, thus allowing you to mix layout with programming. While this may simplify coding for small sites, it does carry the potential to be abused, resulting in difficult to manage or maintain code for larger projects. Proper use of a templating system such as Smarty should do wonders towards preventing that. PHP is available for most operating systems including Unix and Windows, and is an excellent server-side programming language for professional programming.