PHP allows you to separate HTML code from scripted elements. Not only can this make life easier for you as a programmer, but it also can remove obstacles that stand in the way of effective and flexible design.
PHP is designed to run on many operating systems and to cooperate with many servers and databases. You can build for a Unix environment and shift your work to NT without a problem. You can test a project with Personal Web Server and install it on a Unix system running on PHP as an Apache module.
PHP is truly cross-platform. It runs on the Windows operating system; most versions of Unix, including Linux; and Macintosh OS X.
Support is provided for a range of Web servers including Apache (itself open-source and cross-platform), Microsoft Internet Information Server, WebSite Pro, the iPlanet Web Server, and Microsoft's Personal Web Server. The latter is useful if you want to test your scripts offline on a Windows machine, although Apache can also be run on Windows.
There are lot of other server scripting languages, such as ASP, Perl, and Java Servlets, can we say that PHP shows solid performance compared with other's.
We can say that PHP shows solid performance compared with other server scripting languages, such as ASP, Perl, and Java Servlets because of the powerful zend engine. To further improve performance, you can acquire a caching tool (Zend Accelerator), it stores compiled code in memory, eliminating the overhead of parsing and interpreting source files for every request.
The basics of PHP in 24 hours. PHP provides an enormous wealth of functions that allow you to do things for which you would have to write custom code in other languages.