We can make an event with jquery when we take our mouse over any element. We need to get an class, id or any unique identification of element to perform better result. In the same time when we move our mouse from certain div we can bind that event too with some sort of jquery code.
Below id the jquery with animate property in it.
$('.previous').hover(function() {
$(".left_arrow").animate({'left':"-61px"},{duration:500})
}, function(){
$(".left_arrow").animate({'left':"21px"},{duration:0});
});