<style>
	.ani01 div	{
		background: red; width: 50px; height: 50px;
		margin: 10px; padding: 10px; position: relative;
	}
	.ani01 div.blue {background: blue;}
</style>
<script>
	$(function(){
		$('.ani01 button').click(function() {
			$('.ani01 div').animate({
				opacity: 0.5,
				left: '+=100',
				}, 500,"swing", function() {
				$('.ani01 div').toggleClass('blue');//アニメーション終了後に実行
			});
		});
	});
</script>
<div class="ani01">
	<div>要素1</div>
<button>button</button>
</div>