PHP variables / error message for login

[wwjd_kilden]

Help programmers

I've stolen some code : PHP Login script tutorial
to find out how to make logins using PHP. All well so far, only I adjusted for mysqli and altered the chec_klogin page to contain a bit of code saying

else{
header("location:main_login.php");
}

...to send the user back to the login if the login info fails

In doing this, it would make sense to tell the user why they are back at a blank login (ie the standard "Username or password incorrect, please try again." - How do I do this when the login page and the login check are in different files?
(I'm not terribly good with PHP yet).

Do I use session variables? If so: How do I check (at the login page) whether or not it is relevant to output the message?
Or something else?

*scratches head*

 

[G4JC]

I'm not a PHP programmer, but I found this. It includes an error page and a few security features:
How to Create a Secure Login Script in PHP and MySQL

 

[wwjd_kilden]

ok, thanks, I'll have a look at it

 

[JasonNosneh]

There is a ton of ways to handle a login system.

One option is to have a login page and you either post back to same page and conditionally handle GET and POST requests or just POST to another page for processing the login. The other option is to make an ajax request to the server using javascript.

If you are just wanting a simple redirect back to the login page on error, googling "PHP redirect" should be all you need or you could use javascript to do it. When you redirect back to the login page just pass an error message/identfier as a query parameter.

for example,

somewebsite.com?error=2

switch($_GET["error"]){
case 1:
//some error 1
break;
case 2:
//some error 1
break;
case 3:
//some error 1
break;
default:
//no error
}