From http://blog.michellebu.com/2013/03/21-nested-callbacks/

patience.js

$(document).ready(function(){
	$(".disappear").click(function(){
		$("#row20").animate({ "opacity": "0" },
			100,
			function(){$("#row19").animate({ "opacity": "0" },
				100,
				function(){$("#row18").animate({ "opacity": "0" },
					100,
					function(){$("#row17").animate({ "opacity": "0" },
						100,
						function(){$("#row16").animate({ "opacity": "0" },
							100,
							function(){$("#row15").animate({ "opacity": "0" },
								100,
								function(){$("#row14").animate({ "opacity": "0" },
									100,
									function(){$("#row13").animate({ "opacity": "0" },
										100,
										function(){$("#row12").animate({ "opacity": "0" },
											100,
											function(){$("#row11").animate({ "opacity": "0" },
												100,
												function(){$("#row10").animate({ "opacity": "0" },
													100,
													function(){$("#row9").animate({ "opacity": "0" },
														100,
														function(){$("#row8").animate({ "opacity": "0" },
															100,
															function(){$("#row7").animate({ "opacity": "0" },
																100,
																function(){$("#row6").animate({ "opacity": "0" },
																	100,
																	function(){$("#row5").animate({ "opacity": "0" },
																		100,
																		function(){$("#row4").animate({ "opacity": "0" },
																			100,
																			function(){$("#row3").animate({ "opacity": "0" },
																				100,
																				function(){$("#row2").animate({ "opacity": "0" },
																					100,
																					function(){$("#row1").animate({ "opacity": "0" },
																						100)})})})})})})})})})})})})})})})})})})})
	});
	
	$(".reappear").click(function(){
		$("#row20").animate({ "opacity": "1" },
			100,
			function(){$("#row19").animate({ "opacity": "1" },
				100,
				function(){$("#row18").animate({ "opacity": "1" },
					100,
					function(){$("#row17").animate({ "opacity": "1" },
						100,
						function(){$("#row16").animate({ "opacity": "1" },
							100,
							function(){$("#row15").animate({ "opacity": "1" },
								100,
								function(){$("#row14").animate({ "opacity": "1" },
									100,
									function(){$("#row13").animate({ "opacity": "1" },
										100,
										function(){$("#row12").animate({ "opacity": "1" },
											100,
											function(){$("#row11").animate({ "opacity": "1" },
												100,
												function(){$("#row10").animate({ "opacity": "1" },
													100,
													function(){$("#row9").animate({ "opacity": "1" },
														100,
														function(){$("#row8").animate({ "opacity": "1" },
															100,
															function(){$("#row7").animate({ "opacity": "1" },
																100,
																function(){$("#row6").animate({ "opacity": "1" },
																	100,
																	function(){$("#row5").animate({ "opacity": "1" },
																		100,
																		function(){$("#row4").animate({ "opacity": "1" },
																			100,
																			function(){$("#row3").animate({ "opacity": "1" },
																				100,
																				function(){$("#row2").animate({ "opacity": "1" },
																					100,
																					function(){$("#row1").animate({ "opacity": "1" },
																						100)})})})})})})})})})})})})})})})})})})})
	});
});