Question

I have a login page called signin.php where a user can enter an email and password. On clicking submit button, page directs to connection_validate.php. This page validates the user entered data with database. If it’s a registered user, the page directs to calendar.php. If the entered data is incorrect, it should redirect to signin.php. If the entered data is incorrect, I have placed cookie like this:

//action to be done if e mail id and password matches with database records             
if(mysql_num_rows($result)>0)
{
    header('location:calendar.php');
}
//action to be done if e mail id and password does not matches with database records 
else
{
    setcookie('message','incorrect login data');
    header('location:signin.php');
}

In signin.php, I have written the code for displaying an alert if login information is incorrect like this:

<?php
include("include/minfooter.php"); 
if(isset($_COOKIE["message"]))
{
    if(!($_COOKIE["message"]==" "))
    {
        echo "<script>
    alert('Incorrect login information');
    </script>";
    setcookie("message"," ",time()-3600);
    }
}
?>

My issue is that alert is displaying each time when I load the signin page if I have entered a error login data once. If I press the back button from the calendar.php to signin.php also, alert starts showing. I understood that the problem is with cookie. Cookie has not been removed. How can I solve this issue?

Answer 1

Update your signin.php as follows

<?php
    include("include/minfooter.php");
    if (isset($_COOKIE["message"]))
    {

        echo "<script>
                var delete_cookie = function(name) {
                    document.cookie = name + '=;expires=Thu, 01 Jan 1970 00:00:01 GMT;';
                };
                var msg = '" . $_COOKIE["message"] . "';
                if (msg != '')
                    alert('Incorrect login information');
                delete_cookie('message');
            </script>";
    }
?>