PHP预定义变量

  
    echo $_SERVER['PHP_SELF'],"
";//输入执行当前脚本的文件名
    echo $_SERVER['DOCUMENT_ROOT'],"
";//获取网站根目录
    echo $_SERVER['SERVER_ADDR'],"
";//返回运行当前脚本的服务器的IP，如果是本机就是127.0.0.1
    echo $_SERVER['SERVER_NAME'],"
";//服务器主机名称
    echo $_SERVER['SERVER_PORT'],"
";//服务器主机端口
    echo $_SERVER['SERVER_SIGNATURE'],"
";//包含服务器版本和虚拟主机字符串
    echo $_SERVER['REQUEST_METHOD'],"
";//访问页面时的请求方法（GET HEAD POST PUT）
    echo $_SERVER['REMOTE_ADDR'],"
";//返回浏览当前页面的用户的IP地址
    /*
    函数 getenv : 
    Gets the value of an environment variable（得到各种环境变量的值）， 
    返回值： 
    Returns the value of the environment variable varname, or FALSE on an error（失败的话返回 FALSE）
    */
    getenv('REMOTE_ADDR'); //这个函数也是返回浏览当前页面的用户的IP地址
    echo $_SERVER['REMOTE_HOST'],"
";//正在浏览当前页面的用户的主机名，反向解析'SERVER_ADDR'
    echo $_SERVER['REMOTE_PORT'],"
";//正在浏览当前页面的用户的主机端口
    echo $_SERVER['SCRIPT_FILENAME'],"
";//当前执行脚本的绝对路径
    echo $_COOKIE,"
";//通过HTTP COOKIE传递到脚本的信息
    echo $_SESSION,"
";//包含与所有会话有关的信息
    echo $_POST,"
";//包含通过post方法传递参数的信息
    echo $_GET,"
";//包含通过get方法传递参数的信息

    $zy="123456";
    $zzy="1234567";
    $GLOBALS['zy'] = "123456";
    global $zzy;

    echo $GLOBALS,"
";//有所有一定以全局变量组成的数组
?>

/array.php
D:/PHP/testApp
127.0.0.1
localhost
8080

GET
127.0.0.1

53226
D:/PHP/testApp/array.php
Array

Array
Array
Array

---

    function test() {
        $foo = "local variable";
        echo '$foo in global scope: ' . $GLOBALS["foo"] . "
";
        echo '$foo in current scope: ' . $foo . "
";
    }

    $foo = "Example content
";
    test();
?>

$foo in global scope: Example content

$foo in current scope: local variable