是否可以使用ajax发送一个php会话变量？

我在index.PHP中得到了这个

    <?PHP

    include_once '..\connect.PHP';

    session_start();

    if (isset($_SESSION['username'])){
        $player_name = $_SESSION['username'];

    } else {    
        header( 'Location: http://localhost/Inventory/index.PHP' ) ;
        exit;
    }

    ?>

我正在向request.PHP发出ajax请求

    <?PHP
    //connect to databate and check for errors
    $con = MysqL_connect ("localhost","root","");
    if (!$con) {
        die ('Could not connect to database: ' . MysqL_error());
    }

    //select database and check selection
    if (!MysqL_select_db ("GotA", $con)) {
        die ('Could not select database: ' . MysqL_error());
    }

//I have to create this if not it doesnt find the sessions $player_name variable
    $player_name = $_POST['name']; 

    //***Create Player Array**//
    $player_info = "SELECT * from players where id = $player_name";
    $player_info2 = MysqL_query($player_info) or die ('Couldnt get players name');
    $player_info3 = MysqL_fetch_array($player_info2);

好吧,使用javascript发送的变量从数据库中检索数据似乎不安全,有没有办法直接使用index.PHP(会话部分)中的变量？
或者用javascript传递信息是否安全？

解决方法:

你为什么不在request.PHP中再次检索会话？

代替：

$player_name = $_POST['name']; 

使用：

$player_name = $_SESSION['username']; 

另外一定要在此之前使用session_start().