if (document.images)  {
panel_log = new Image
panel_rejestr = new Image
panel_obserw = new Image
panel_menu = new Image
panel_log.src = 'grafika/panel_log.jpg'
panel_rejestr.src = 'grafika/panel_rejestr.jpg'
panel_obserw.src = 'grafika/panel_obserw.jpg'
panel_menu.src = 'grafika/leftmenu.jpg'
}  else  {
panel_log = ""
panel_rejestr = ""
panel_obserw = ""
panel_menu = ""
document.panelMenu = ""
}