PHP中未定义的变量错误。我怎样才能修好它？

我有一个错误：

注意：未定义的变量：pollid

这里怎么了

<?php
    $pollid = $_GET['pollid'];
    $connect = mysqli_connect('localhost', 'root','test','apklausa1');
    $query = "SELECT * FROM polls WHERE pollid='$pollid'";
    $q = mysqli_query($connect, $query);

    while($row = mysqli_fetch_array($q)) {
        $id = $row[0];
        $title = $row[1];
        $pollid = $row[2];
        $ipaddress = $row[3];
        echo "<h1>$title</h1>";
?>

        <table>
            <form action="" method="POST">

<?php
            $questions = "SELECT * FROM questions WHERE pollid='$pollid'";
            $q2 = mysqli_query($connect, $questions);
            while($r = mysqli_fetch_array($q2)) {
            $question = $r[1];
            $votes = $r[2];
            $newvotes = $votes + 1;
            $ip = $_SERVER['REMOTE_ADDR'];
            $newipaddress = $ipaddress."$ip,";

            if (isset($_POST['vote'])) {
                $polloption = $_POST['polloption'];
                if ($polloption == "") {
                    die("You didn't select an option.");
                } else {

                        $ipaddresse = explode(",", $ipaddress);
                        if (in_array($ip, $ipaddresse)) {
                            die("You've already voted");
                        } else {
                    mysqli_query($connect, "UPDATE questions SET votes='$newvotes' WHERE pollid='$pollid' AND question='$polloption'");
                    mysqli_query($connect, "UPDATE polls SET ipaddress='$newipaddress' WHERE pollid='$pollid'");
                    die("You voted Successfully");
                    }
                }
            }

            echo
              '<tr><td>' . $question .
              '</td><td><input type="radio" name="polloption" value="' .
              $question .
              '" /> ' . $votes .
              ' votes</td></tr>';
        }
    }

?>

---

您需要查看
$\u GET['pollid']
的值来自何处

可能是因为变量
$pollid
没有获取该值，所以出现了错误。因此，它被取消设置，并显示一条错误消息。请检查发出HTTP GET请求的表单。收到值后，问题将得到解决。
$\u GET['pollid']
未声明

在某些情况下，
$\u GET
和
$\u POST
变量可能没有声明。使用
isset（）
可以帮助您检查变量是否已声明

比如说,

if(isset($_GET['pollid']))
{
   // Your code here
}

$\u GET['pollid']
未定义或没有值您可以指定行号吗