Code executing both if and else statements together how do i fix? - php

Question

the code is running to match username with password and if both correct redirecting to another page but that and the else statements both run
Code:
if (isset($_POST['Login'])) {
$IncorrectDetails = 0;
$Username=$_REQUEST['Username'];
$Password=$_REQUEST['Password'];
echo "<p> $Username $Password</p>";
$myfile = fopen("bin\Account Details.txt", "r") or die("Unable to open file!");
//reads raw file
$string = fread($myfile,filesize("bin\Account Details.txt"));
//turns the string to array
$a = explode(',', $string);
foreach ($a as $result) {
$b = explode('. ', $result);
$AccountDetails[trim($b[0])] = trim($b[1]);
}
//closes file
fclose($myfile);
print_r($AccountDetails);
foreach ($AccountDetails as $StoredUsername => $StoredPassword) {
if ($StoredUsername == $Username){
if ($StoredPassword == $Password) {
header('Location: Main.php');
}
else {
$IncorrectDetails = 1;
}
}
else {
$IncorrectDetails = 1;
}
}
if ($IncorrectDetails == 1){
echo "<script type='text/javascript'>alert('Incorrect login details');</script>";
}
}
its expected to come up with a popup when incorrect and redirect when correct

Answer 1

if (isset($_POST['Login'])) {
$IncorrectDetails = 0;
$Username=$_REQUEST['Username'];
$Password=$_REQUEST['Password'];
echo "<p> $Username $Password</p>";
$myfile = fopen("bin\Account Details.txt", "r") or die("Unable to open file!");
//reads raw file
$string = fread($myfile,filesize("bin\Account Details.txt"));
//turns the string to array
$a = explode(',', $string);
foreach ($a as $result) {
$b = explode('. ', $result);
$AccountDetails[trim($b[0])] = trim($b[1]);
}
//closes file
fclose($myfile);
foreach ($AccountDetails as $StoredUsername => $StoredPassword) {
if ($StoredUsername == $Username && $StoredPassword == $Password){
$CorrectDetails = 1;
} else {
$IncorrectDetails = 1;
}
}
if(isset($CorrectDetails) && $CorrectDetails == 1){
header('Location: Main.php');
}else ($IncorrectDetails == 1){
echo "<script type='text/javascript'>alert('Incorrect login details');</script>";
}
}
You are redirect to another page it's not a proper way instead of that you can use a variable just like you have used in else and outside the loop you can redirect to another page.

Answer 2

That's beacuse the redirection is not instantaneus, php code still being processed.
So, just after header('Location: Main.php'); do exit; to stop at all your script in that point, and let the redirection works.
header('Location: Main.php');
exit;
Also, you musn't print anything before the header() instruction (remove print_r()).