jQuery("document").ready(function($){
	
	$(this).find("#js_map area").each( function(index) {
		$(this).attr("id","js_area_"+(index+1));
	});
	var mapposition = $("#imap").css('background-position');
	$("#js_map").css('background-position', mapposition);
	$("#js_map area").hover(
		function(){
			var imgheight = $(this).parents("#js_map").find("img").attr("height");
			var factor = $(this).attr("id").substr(8);
			var position = "0px "+imgheight*factor*-1 + "px";
			$(this).parents("#js_map").css('background-position', position);
		}, function(){
			$(this).parents("#js_map").css('background-position', mapposition);
		}
	);
	
});