function swap_image(image_id,new_src) {
	$(image_id).src = new_src;
}

var timeouts = new Array();

function clear_dropdown(menu_item_id) {
	clearInterval(timeouts['swap_' + menu_item_id]);
	clearInterval(timeouts['fade_' + menu_item_id]);
}

function drop_on(menu_item_id) {
	if(Element.getStyle($(menu_item_id + '_dropdown'),'display') != 'none') {
		clear_dropdown(menu_item_id);
	} else {
		Element.setOpacity($(menu_item_id + '_dropdown'),'0');
	}
	var margin_left = 1;
	var margin_top = 2;
	Element.setStyle($(menu_item_id + '_dropdown'),{'left': Position.cumulativeOffset($(menu_item_id))[0] + margin_left + "px"} );
	Element.setStyle($(menu_item_id + '_dropdown'),{'top': Position.cumulativeOffset($(menu_item_id))[1] + Element.getHeight($(menu_item_id)) + margin_top + "px"} );
	swap_image(menu_item_id,"images/" + menu_item_id + "_on.gif");
	Effect.Appear(menu_item_id + "_dropdown",{duration: 0.15, queue:'end'});
}

function drop_off(menu_item_id) {
	timeouts['swap_' + menu_item_id] = setTimeout("swap_image('" + menu_item_id + "','images/" + menu_item_id + "_off.gif')",250);
	timeouts['fade_' + menu_item_id]  = setTimeout("Effect.Fade('" + menu_item_id + "_dropdown" + "',{duration: 0.10, queue:'end'})",250);
}