use stop(true,true) in Jquery.We can use create a nice slide effect without the common problem of multiple queued animations by adding .stop(true, true) to the chain:
$(document).ready(function(){
$('#test').hover(
function(){
$('.caption').stop(true,true).show('slide', {direction: 'left'}, 1200);
},
function(){
$('.caption').stop(true,true).hide(100)});
});