session variables in ajax call

i have set a session variable like this in index page

if(!isset($_SESSION['adpages'])) $_SESSION['adpages'] = 0;

i have another php for simple ajax example like when i click a button it calls ajax.php

if(isset($_SESSION['adpages']))
{
$_SESSION['adpages'] = $_SESSION['adpages']+ 1;
echo "here".$_SESSION['adpages'] ;
}
else
{
$_SESSION['adpages'] = 0;
echo "here not ".$_SESSION['adpages'] ;
}

but it always showing here not 0

any idea to fix this

 

Do you start the ajax.php with function session_start()??

 

the same qurestion?

 

yeah i realized that after posting here that was the problem and i fixed that thanks for reply