function showUserDetails( userID )
{
   window.open("user_details.php?userID="+userID,"UserDetails","toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=yes, copyhistory=yes, width=400, height=450, screenX=100, screenY=100");
}

function showBenutzungsordnung()
{
   window.open("acceptbenutzungsordnung.php","Benutzungsordnung","toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=yes, copyhistory=yes, width=500, height=600, screenX=100, screenY=100");
}