rtrim，dirname，魔术常量用法

$str = "Hello World!!!";
echo $str . "<br>";
echo rtrim($str,"!d");

Hello World!!!
Hello Worl

$str = "Hello World!a!";
echo $str . "<br>";
echo rtrim($str,"!d");

Hello World!a!
Hello World!a

从字符串右侧开始查找，只要满足第二个参数则去掉，直到不满足则停止

header('Content-type:text/html;charset=utf8');
define('ROOT' , dirname(__DIR__));
//dirname是往上跳一层目录
//魔术常量只取决于放置文件的位置
/*echo __DIR__,'<br>';
echo __FILE__ , '<br>';
echo __LINE__;*/
require(ROOT . '/lib/mysql.php');
require(ROOT . '/lib/func.php');

sql之left join、right join、inner join的区别

http://www.cnblogs.com/pcjim/articles/799302.html

不调用mysql_close()出现的问题

JWT 在前后端分离中的应用与实践

http://www.open-open.com/lib/view/open1433995002942.html