Why can't I access session variables from my AJAX-called PHP script?

Question

I have one PHP script with a session variable, set like so:

$_SESSION[\'VAR1\'] = \"test\"

Now, I am using AJAX via a jQuery-initiated POST

Answer 1

An addendum to what Salman A wrote:

If you set a session variable in an https:// file and try to access it with a http:// file you will not be able to...

https://www.example.com/index.php - call session_start() and set session variable
http://ww.example.com/index_tmp.php - unable to access session variable

and vice versa...

http://www.example.com/index.php - call session_start() and set session variable
https://ww.example.com/index_tmp.php - unable to access session variable

Rather:

https://www.example.com/index.php - call session_start() and set session variable
https://ww.example.com/index_tmp.php - Able to access session variable

And:

http://www.example.com/index.php - call session_start() and set session variable
http://ww.example.com/index_tmp.php - Able to access session variable