function webcam_popup(mit)
{
  pwinwidth = 640 ;
  pwinheight = 544 ;
  winleft = 20 ;
  wintop = 20 ;
  winprop = 'menubar=no,scrollbars=no,resizable=no,noresize,width='
            + pwinwidth + ',height=' + pwinheight + ',left=' + winleft
            + ',top=' + wintop ;

  window.open( mit, 'webcam_popup', winprop ) ;
}