php登录：未定义索引

我对php非常陌生，这是我第一次登录。 因此，当我从数据库输入有效的用户名和密码时，我会遇到以下两个错误：

注意：第3行未定义索引：brukernavn

注意：未定义索引：第4行的密码

$username = $_POST['brukernavn'];
$password = $_POST['passord'];

if($username&&$password)
{

$connect = mysql_connect("localhost", "root", "") or die ("Cannot connect");
mysql_select_db("prosjekt") or die ("Cant find db");

$query = mysql_query("SELECT * FROM bruker WHERE brukernavn='$username'");

$radnum = mysql_num_rows($query);

if ($radnum!=0)
{

while ($rad = mysql_fetch_assoc($query))
{
    $dbuser = $rad['brukernavn'];
    $dbpass = $rad['passord'];
}

if ($username==$dbuser&&$password==$dbpass)
{
echo "Logged in";
}
else
    echo "Wrong username or password";

}
else
    die("That user does not exist!");


}
else
    die("Please enter a username and password!");




?>

---

有人知道我哪里出错了吗？

您正在尝试访问两个尚未分配的变量：

$username = $_POST['brukernavn'];
$password = $_POST['passord'];

你可以：

需要将登录代码包装在

if

语句中，以检查表单是否已提交

在访问变量值之前，需要检查这些变量是否已设置

希望这有助于

 <?

$username = $_POST['brukernavn']; 
$password = $_POST['passord'];

if (isset ($_POST['submit'])) { // on form submit... make sure the html form input submit is name='submit' then this script will work

    if($username&&$password)
        {

        $connect = mysql_connect("localhost", "root", "") or die ("Cannot connect");
        mysql_select_db("prosjekt") or die ("Cant find db");

        $query = mysql_query("SELECT * FROM bruker WHERE brukernavn='$username'");

        $radnum = mysql_num_rows($query);

            if ($radnum!=0)
                {

                while ($rad = mysql_fetch_assoc($query))
                {
                    $dbuser = $rad['brukernavn'];
                    $dbpass = $rad['passord'];
                }

                if ($username==$dbuser&&$password==$dbpass)
                {
                echo "Logged in";
                }
                else
                    echo "Wrong username or password";

                }
            else
                die("That user does not exist!");


        }
    else
        die("Please enter a username and password!");

    }


?>

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您应该阅读本主题，了解登录脚本的最佳实践：可能重复的