PHP会话变量在刷新时被破坏

Question

每次刷新页面时，用户都会注销并重定向到index.php。我猜测我还没有正确设置会话变量。我在本地工作得很好，但没有把它移到临时服务器上。

处理登录的文件。如果需要，我可以从其他文件发布代码：

<?php 
    session_start();
    include('global.php');
    if(isset($_POST["login"])) {
        $email = db_quote($_POST['email']);
        $password = db_quote($_POST['password']);
        $type = db_quote($_POST['timesheettype']);
        $_SESSION['login'] = "";

        if(empty($_POST['email']) || empty($_POST['password'])) {
            phpAlert("Please complete all form fields");
            echo "<script>window.location.href = '../timesheetmanager/index.php';</script>";
        }
        else {
            $query = db_select("SELECT * FROM timesheetlogin WHERE email = {$email} AND password = {$password}");

            if($query == false) {
                phpAlert("Sorry those details are incorrect.");
                echo "<script>window.location.href = 'index.php';</script>";
            }
            else {
                $_SESSION['login'] = $query[0]["id"];
                header ("Location: main.php");
            }
        }   
    }

main.php中的代码

    <?php
        session_start();
        //$query = $_SESSION['login'];
        $id = $_SESSION['id'];
        $type = $_SESSION['type'];
        $name = $_SESSION['name'];
        include('header.php');
        echo $_SESSION['id'];
    ?>

    <div class="content grid-70">
        <h2>Timesheet Manager Home</h2>
        <?php
                if ($type == "cand") {
                      $tscandquery = db_select("SELECT * FROM timesheets WHERE candid={$id} AND status=\"cand\"");
                      $tsclientquery = db_select("SELECT * FROM timesheets WHERE candid={$id} AND status=\"client\"");
                      $tscandresult = count($tscandquery);
                      $tsclientresult = count($tsclientquery);
                $_SESSION['tscandresult'] = $tscandresult;
                $_SESSION['tsclientresult'] = $tsclientresult;

                        if($tscandresult == "0" && $tsclientresult == "0") { ?>
                              <p>All of your timesheets are up to date</p>
                <?php }

                        if($tscandresult != "0") { ?>
                              <p>You currently have <?php echo $tscandresult; ?> timesheets awaiting your submission</p>
                    <a href="timesheets/candidate-list.php">View your Active Timesheets</a>
                <?php }

                        if($tsclientresult != "0") { ?>
                              <p>You currently have <?php echo $tsclientresult; ?> timesheets awaiting supervisor's approval.</p>
                <?php }
                }
                if ($type == "client") {
                      $tscandquery = db_select("SELECT * FROM timesheets WHERE clientid={$id} AND status=\"cand\"");
                      $tsclientquery = db_select("SELECT * FROM timesheets WHERE clientid={$id} AND status=\"client\"");
                      $tscandresult = count($tscandquery);
                      $tsclientresult = count($tsclientquery);
                $_SESSION['tscandresult'] = $tscandresult;
                $_SESSION['tsclientresult'] = $tsclientresult;

                        if($tscandresult == "0" && $tsclientresult == "0") { ?>
                              <p>All of your timesheets are up to date</p>
            <?php }

                if($tscandresult != "0") { ?>
                              <p>You currently have <?php echo $tscandresult ?> timesheets awaiting candidate submission</p>
            <?php }

                        if($tsclientresult != "0") { ?>
                              <p>You currently have <?php echo $tsclientresult; ?> timesheets awaiting your approval</p>
                    <a href="timesheets/client-list.php">View Timesheets awaiting approval</a>
            <?php }
                } ?>
    </div>
    <div class="grid-30 no-padding">
    <?php
        include('rh-nav.php');
    ?>
    </div>

    </div>

    <?php
        include('footer.php');
    ?>