实现tabs动画效果滚动

document.getElementById('over').scrollLeft：实现元素向右进行滚动

setInterval：通过定时器实现滚动

var interval = setInterval(function() {
	var scrollLeft = document.getElementById('over').scrollLeft
	scrollLeft += 10;
        if (scrollLeft > 350) {
	clearInterval(interval)
		}
 }, 20)