Super global variable $ globals in the php Tutorial: contains a reference variable that is valid globally for each current script. The key of the array is the name of the global variable. $ Globals array exists from php 3.
$ _ Server: variables are set by the web server or directly associated with the execution environment of the current script. Similar to the old $ http_server_vars array (still valid, but not used ).
$ _ Get: the variable submitted to the script through the http get method.
$ _ Post: the variable submitted to the script through the http post method.
$ _ Cookie: variables submitted to the script through http cookies.
$ _ Files: variables submitted to the script by uploading the http post file.
Enctype = "multipart/form-data" must be included in the file upload form"
$ _ Env: the variable submitted to the script in the execution environment.
$ _ Request: the variables submitted to the script through get, post, and cookie mechanisms. Therefore, this array is not trustworthy. All the existence or not of the variables contained in the array and the Order of the variables are defined according to the variables_order configuration instructions in php. ini. This array does not directly simulate earlier versions of php 4.1.0. See import_request_variables ().
Note: Since php 4.3.0, the file information in $ _ files no longer exists in $ _ request.
$ _ Session: the variable currently registered to the script session.