var menu_position = new Array();
	// offsets between items of the same level
menu_position['top'] = [null, 19, 19, 19];
menu_position['left'] = [null, null, null, null];
	// item sizes for different levels of menu
menu_position['height'] = [25, 20, 20, 20];
menu_position['width'] = [null, null, null, null];
	// menu block offset from the origin:
	//	for root level origin is upper left corner of the page
	//	for other levels origin is upper left corner of parent item
menu_position['block_top'] = [64, 24, null, null];
menu_position['block_left'] = [0, null, null, null];
	// time in milliseconds before menu is hidden after cursor has gone out
menu_position['hide_delay'] = [400, 400, 400, 400];
	// path to gif containing one transparent pixel
menu_position['pixel_path'] = 'http://www.romm.gov.sg/romm/images_common/shim.gif';