session_start();    //开启session

$_SESSION['test'] = time();            //通过全局变量$_SESSION,写入一个session

echo "session_id:".session_id();      //显示当前的session_id

echo "<br>";

echo $_SESSION['test'];              //通过全局变量$_SESSION，读取一个session

unset($_SESSION['test']);          //销毁一个session

echo "<br>";

var_dump($_SESSION);

//session_id:lpd56n5qsmga006v3ss300sgf4

//1518599397

//array(0) {

//}

setcookie('test', '', , '/');  //name, value, expire, path

echo $_COOKIE['test'];

//

setcookie('test', '', time()-)   //删除cookie(删除test的cookie值)