On this page, you will find a table of the keys that are defined in PHP's $_SERVER superglobal array running on Apache and IIS servers. The purpose of this table is to allow PHP developers an insight of what to expect if they must migrate from one platform to another. The data found in this table was compiled using Apache 1.3.29 running PHP 4.3.4 as a module and IIS 5.1 running PHP 4.3.3. Keys