PHP login form not working after uploading the website

Question

EDIT: There are invisible spaces after the PHP tag. I removed them, and it's now working.

So I have this website project that was built for 4 weeks. THE LOGIN FORM HERE IS WORKING.

This is the code for the login.php

<?php
 session_start(); // Starting Session
 $error=''; 

 if (isset($_POST['ComeIn'])) { //NAME OF THE BUTTON CLIKED

if (empty($_POST['email']) || empty($_POST['pwd'])) {   //IF EMPTY
$error = "Username or Password is invalid";
}
else 
    {

        $username=$_POST['email'];
        $password=$_POST['pwd'];
        include ('connection.php');


        $username = mysql_real_escape_string($username);
        $password = mysql_real_escape_string($password);


        $query = mysql_query("SELECT * from user_account where Password='$password' AND Email='$username'", $connection);
        $row1= mysql_fetch_array($query);
        $rows = mysql_num_rows($query);

            if ($rows == 1) {   //IF OK
                if ($row1['AccType'] == "Teacher")
                {
                    $_SESSION['login_user']=$username; // Initializing Session
                    header("location: teachers/teacherprofile.php"); // Redirecting To Other Page
                }
                else if ($row1['AccType'] == "Student")
                {
                    $_SESSION['login_user']=$username; // Initializing Session
                    header("location: students/studentprofile.php"); // Redirecting To Other Page
                }

                else
                {
                    echo ("<script language = 'Javascript'>
                            window.alert('Incorrect Input!')
                            window.location.href='index.php'
                            </script>");
                }
            } else 
                {
                    echo ("<script language = 'Javascript'>
                            window.alert('Incorrect Input!')
                            window.location.href='index.php'
                            </script>");
                }
                }

        mysql_close($connection); 
    }

?>

But this admin login form is not working and it has almost the same code. It's not going anywhere. It's just going to login2.php and none of the PHP functions are working. Below is the login2.php:

<?php
session_start(); // Starting Session
$error=''; 
include ('connection.php');



if (isset($_POST['login'])) { //NAME OF THE BUTTON CLIKED

    if (empty($_POST['aemail']) || empty($_POST['apwd'])) { //IF EMPTY
    $error = "Username or Password is invalid";
    }
    else //TEXTFIELDS NOT EMPTY
        {

            $username=$_POST['aemail'];
            $password=$_POST['apwd'];
            include ('connection.php');


            $username = mysql_real_escape_string($username);
            $password = mysql_real_escape_string($password);


            $query = mysql_query("SELECT * from service_account where CS_Password='$password' AND CS_Email='$username'", $connection);
            $row1= mysql_fetch_array($query);
            $rows = mysql_num_rows($query);



                if ($rows == 1) {   //IF OK
                    if ($row1['SA_Type'] == "Admin")
                    {
                        $_SESSION['login_user']=$username; // Initializing Session
                        header("location: admin/admin_dashboard.php"); // Redirecting To Other Page
                    }
                    else if ($row1['SA_Type'] == "Customer Service")
                    {
                        $_SESSION['login_user']=$username; // Initializing Session
                        header("location: cservice/cs_inquiry.php"); // Redirecting To Other Page
                    }
                    else
                    {
                        $error = "Username or Password is invalid";
                        header("location: login_csa.php");
                    }
                } else 
                    {
                    $error = "Username or Password is invalid";
                    header("location: login_csa.php");
                    }

            mysql_close($connection); 
        }
}

?>

Im debugging this for two days now. THe weird part is, When I tried to use the system in localhost, it's perfectly working. When I put it in iPage.com, that happens. Any suggestions?

Answer 1

This is a common occurrence and is called "The White Screen of Death". You should turn on error reporting at the top of your script to figure out what the issue is, that's causing this!

<?php
ini_set('display_errors', 1);
error_reporting(-`);

^{Note: This is almost always because output was sent to the browser before you tried to start a session or do something.}

The above will tell you exactly what the issue was, and in your case it did. Stating:

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /hermes/bosoraweb126/b1216/ipg.meteacherscom/login2.php:2) in /hermes/bosoraweb126/b1216/ipg.meteacherscom/login2.php on line 4

Now if you didn't have anything echo'ing to the screen before you started the session, then your issue would have to be some invisible characters within your PHP script.

If that's your case (which it seems, was), then you should follow this answer below to remove those invisible characters (bad encoding). Your script will run again properly.

• Clean source code files of invisible characters