function highlight(menu)
{document.getElementById(menu+'_left').style.background="url('images/menu_top_deco_left.jpg') no-repeat top left";document.getElementById(menu+'_right').style.background="url('images/menu_top_deco_right.jpg') no-repeat top left";}
function undo_highlight(menu)
{document.getElementById(menu+'_left').style.background="";document.getElementById(menu+'_right').style.background="";}
function highlight_town(town)
{town.src='images/menu_deco_yellow.jpg';}
function undo_highlight_town(town)
{town.src='images/menu_mapa_deco.jpg';}