有這些

• $GLOBALS
• $_SERVER
• $_REQUEST
• $_POST
• $_GEST
• $_FILES
• $_ENV
• $_COOKIE
• $_SESSION

$_GLOBALS

用於在函式中（或者區域性作用域中）呼叫全域性變數

$_SERVER

$_SERVER 是一個包含了諸如頭資訊(header)、路徑(path)、以及指令碼位置(script locations)等等資訊的陣列

由伺服器建立

<?php 
echo $_SERVER['PHP_SELF'];
echo "<br>";
echo $_SERVER['SERVER_NAME'];
echo "<br>";
echo $_SERVER['HTTP_HOST'];
echo "<br>";
echo $_SERVER['HTTP_REFERER'];
echo "<br>";
echo $_SERVER['HTTP_USER_AGENT'];
echo "<br>";
echo $_SERVER['SCRIPT_NAME'];
?>
 

$_REQUEST

PHP $_REQUEST用於收集HTML表單提交的資料