$_SERVER 函数详解
实例：
1、http://localhost/index.php/Home/H1/index.html
结果：
$_SERVER['QUERY_STRING'] = "";
$_SERVER['REQUEST_URI'] = "/index.php/Home/H1/index.html";
$_SERVER['SCRIPT_NAME'] = "/index.php";
$_SERVER['PHP_SELF'] = "/index.php/Home/H1/index.html";
2、http://localhost/index.php/Home/H1/index.html?key=test (附带查询)
结果：
$_SERVER['QUERY_STRING'] = "key=test";
$_SERVER['REQUEST_URI'] = "/index.php/Home/H1/index.html?key=test";
$_SERVER['SCRIPT_NAME'] = "/index.php";
$_SERVER['PHP_SELF'] = "/index.php/Home/H1/index.html";
由实例可知：
$_SERVER["QUERY_STRING"] 获取查询 语句，实例中可知，获取的是?后面的值
$_SERVER["REQUEST_URI"] 获取 http://localhost 后面的值，包括/
$_SERVER["SCRIPT_NAME"] 获取当前脚本的路径，如：index.php
$_SERVER["PHP_SELF"] 当前正在执行脚本的文件名