div 애니메이션

$('#example').animate({
    'marginLeft' : "+=50px"
});

$('#example').animate({
    'marginLeft' : "-=50px"
});

<script language="javascript">
function example_animate(px) {
	$('#example').animate({
		'marginLeft' : px
	});
}
</script>
<input type="button" value="Move Left" onclick="example_animate('-=50px')" />
<input type="button" value="Move Right" onclick="example_animate('+=50px')" />
<div id="example" style="border: 1px solid black; margin: 10px 0px; padding: 10px; background-color: rgb(238, 238, 238); width: 200px; text-align: center;">This is going to move</div>

출처 : http://www.electrictoolbox.com/jquery-relative-move-div-left-right/