Hackers often use these to try and inject code etc.\u00a0 When accessing superglobal variables ensure you sanitise them.\u00a0 E.g.<\/p>\n
\r\n $CameFromPage = htmlentities($_SERVER['HTTP_REFERER']); \/\/htmlentities() converts things like < > \" \\ etc into HTML strings like < so they become harmless.<\/code><\/pre>\nSuperglobal Variables<\/h4>\n
Always available in all scopes<\/p>\n
$GLOBALS<\/p>\n
References all variables available in global scope<\/p>\n
$_SERVER<\/p>\n
Server and execution environment information<\/p>\n
$_GET<\/p>\n
HTTP GET variables<\/p>\n
$_POST<\/p>\n
HTTP POST variables<\/p>\n
$_FILES<\/p>\n
HTTP File Upload variables<\/p>\n
$_REQUEST<\/p>\n
HTTP Request variables<\/p>\n
$_SESSION<\/p>\n
Session variables<\/p>\n
$_ENV<\/p>\n
Environment variables<\/p>\n
$_COOKIE<\/p>\n
HTTP Cookies<\/p>\n
$php_errormsg<\/p>\n
The previous error message<\/p>\n
$HTTP_RAW_POST_DATA<\/p>\n
Raw POST data<\/p>\n
$http_response_header<\/p>\n
HTTP response headers<\/p>\n
$argc<\/p>\n
The number of arguments passed to script<\/p>\n
$argv<\/p>\n
Array of arguments passed to script<\/p>\n