newwin = null;

function doPopup(f) {
  newwin = window.open('', 'Betaling','scrollbars,status,width=550,height=600');
  newwin.focus();
  if(!self.name) { self.name = 'shopwin'; }
  if (!newwin.opener) { newwin.opener = self; }
  f.opener.value = self.name;
  return true;
} 

newsesswin = null;

function showSessVar(f,u) {
  newsesswin = window.open(u, 'Session variables','scrollbars,status,width=550,height=600');
  newsesswin.focus();
  if(!self.name) { self.name = 'sesswin'; }
  if (!newsesswin.opener) { newsesswin.opener = self; }
  f.opener.value = self.name;
  return true;
}