When refresh page by passing url, why does my session lose?

Question

I try log to other page by url but session lose so it go to login page.

Answer 1

First, carry out these usual checks:

Make sure session_start(); is called before any sessions are being called. So a safe bet would be to put it at the beginning of your page, immediately after the opening <?php tag before anything else. Also ensure there are no whitespaces/tabs before the opening <?php tag.
After the header redirect, end the current script using exit(); (Others have also suggested session_write_close(); and session_regenerate_id(true), you can try those as well, but I'd use exit();)
Make sure cookies are enabled in the browser you are using to test it on.
Ensure register_globals is off, you can check this on the php.ini file and also using phpinfo(). Refer to this as to how to turn it off.
Make sure you didn't delete or empty the session
Make sure the key in your $_SESSION superglobal array is not overwritten anywhere
Make sure you redirect to the same domain. So redirecting from a www.yourdomain.com to yourdomain.com doesn't carry the session forward.
Make sure your file extension is .php (it happens!)
Now, these are the most common mistakes, but if they didn't do the trick, the problem is most likely to do with your hosting company. If everything works on localhost but not on your remote/testing server, then this is most likely the culprit. So check the knowledge base of your hosting provider (also try their forums etc). For companies like FatCow and iPage, they require you to specify session_save_path. So like this:

session_save_path('"your home directory path"/cgi-bin/tmp');
session_start();
(replace "your home directory path" with your actual home directory path. This is usually within your control panel (or equivalent), but you can also create a test.php file on your root directory and type:

<?php echo $_SERVER['SCRIPT_FILENAME']; ?>
The bit before 'test.php' is your home directory path. And of course, make sure that the folder actually exists within your root directory. (Some programs do not upload empty folders when synchronizing)

Answer 2

but I'm using session.