I trying to use an alert message when someone enters incorrect login details, and I then want to redirect them back to the same login page. I'm doing this inside a php file that is called when someone submits a login form. I'm trying something like this:
echo '<script language="javascript">';
echo 'alert("Invalid Username or Password")';
echo 'location.replace("target.php")';
echo '</script>';
but it goes to the php file itself, which shows nothing.