setting session variables via a form

Despite my best efforts, I can't seem to set session variables via a basic form. I'm trying to use a button to alter display settings, which should be a simple task, but apparently it is not. Here's the code I'm working with. <? if( (!isset( $_POST['view_details'] )) && ($_SESSION['item_details'] != "yes") ) { print "<form method=\"post\">"; print "<input type=\"button\" name=\"view_details\" value=\"View Descriptions\" />"; print "</form>"; } else $_SESSION['item_details'] = "yes"; ?> My session I have tried a number of different solutions, including removing session_start() from its calling function and various things I might otherwise overlook. I'm sure that I'm overlooking something easy but I can't figure out what it is. The session variable simply isn't being set, as confirmed by printing its value (and by things not working!). Thanks a lot for any and all suggestions. Edward Dudlik Becoming Digital www.becomingdigital.com