var activePage;

function setActivePage(page){
	activePage = page;
}

function highlight_menu(page){
	var img = document.getElementById('img_'+page);
	img.src = 'images/menu_'+page+'.jpg';
}

function unhighlight_menu(page){
	if (page!=activePage){
		var img = document.getElementById('img_'+page);
		img.src = 'images/menu_'+page+'_hl.jpg';
	}
}