function menu( item, image_name ) {
	var menu_item = document.getElementById(item);
		if( menu_item.style.display == 'block' ){
			menu_item.style.display = 'none';
		}else{
			menu_item.style.display = 'block';
		}
		
}

function sub_menu( item, image_name ) {
	var menu_item = document.getElementById(item);
		if( menu_item.style.display == 'block' ){
			menu_item.style.display = 'none';
		}else{
			menu_item.style.display = 'block';
		}
		
		var home_image = document.images[image_name];

		if( String(home_image.src).indexOf( 'images/menu/m_plus.gif' ) >= 0 ){
			home_image.src = 'images/menu/m_minus.gif';
		}else{
			home_image.src = 'images/menu/m_plus.gif';
		}
		
}