PhP和mySQL测试

我一直在尝试测试登录php，但在输入用户名和密码后，出现了此错误（注意：未定义索引：第12行/web/stud/u1177827/store_admin/admin_login.php中的用户名注意：未定义索引：第13行/web/stud/u1177827/store_admin/admin_login.php中的密码连接失败。该信息不正确，请单击此处重试） 代码如下：

<?php
session_start();
if(isset($_SESSION["staff"])){
    header("location:index.php");
    exit();
}
?>
<?php
// Prase the log in form if the user has filled it out and pressed "Log in"
if(isset($_POST["username"])&& isset($_POST["password"])){

$username=preg_replace('#[^A-Za-z0-0]#i',"",$_SESSION["username"]);//filter everything but numbers and letters
$password=preg_replace('#[^A_Za-z0-9]#i',"",$_SESSION["password"]);//filter everything but numbers and letters
//Connect to the MySQL database
include "../storescripts/connectToMySQL.php";
$sql=mysql_query("SELECT*FROM B4UStaff WHERE fname='$username' AND lname='$password'LIMT 1");//query the person
//..... MAKE SURE PERSON EXISTS IN DATABASE....
$existCount=mysql_num_rows($sql);//count the row nums
if($existCount==1){//evaluate the count
while($row=mysql_fetch_array($sql)){
    $staffNo=$row["staffNo"];
}
$_SESSION["staffNo"]=$staffNo;
$_SESSION["username"]=$username;
$_SESSION["password"]=$password;
header("location:index.php");
exit();
} else{
    echo 'That information is incorrect, try again <a href="index.php">Click Here</a>';
    exit();
}
}
?>

更正这两行而不是会话你必须像这样使用POST

$username=preg_replace('#[^A-Za-z0-0]#i',"",$_POST["username"]);//filter everything but numbers and letters
$password=preg_replace('#[^A_Za-z0-9]#i',"",$_POST["password"]);//filter everything but numbers and letters

只需使用$\u POST更改$\u会话即可：

$_SESSION["username"]
$_SESSION["password"]

到

在代码中，您需要获取这两个POST变量，并使用staffNo将其设置为会话变量，这是正确的

$_POST["username"]
$_POST["password"]