$(function() {
	var cur, pre, next;
	var imgDoms = $('.imgitem');
	initImg();

	function initImg() {
		pre = 0;
		cur = 1;
		next = 2;
		$(imgDoms[pre]).addClass('pre-img');
		$(imgDoms[cur]).addClass('cur-img');
		$(imgDoms[next]).addClass('next-img');
	}
	$('#pre').click(function() {
		pre = pre - 1;
		cur = cur - 1;
		next = next - 1;
		if (next < 0) {
			next = imgDoms.length - 1;
		}
		if (cur < 0) {
			cur = imgDoms.length - 1;
		}
		if (pre < 0) {
			pre = imgDoms.length - 1;
		}
		$('.cur-img').removeClass('cur-img');
		$(imgDoms[cur]).addClass('cur-img');

		$('.pre-img').removeClass('pre-img');
		$(imgDoms[pre]).addClass('pre-img');

		$('.next-img').removeClass('next-img');
		$(imgDoms[next]).addClass('next-img');
	})
	$('#next').click(function() {
		pre += 1;
		cur += 1;
		next += 1;
		if (next > imgDoms.length - 1) {
			next = 0
		}
		if (cur > imgDoms.length - 1) {
			cur = 0
		}
		if (pre > imgDoms.length - 1) {
			pre = 0
		}
		$('.cur-img').removeClass('cur-img');
		$(imgDoms[cur]).addClass('cur-img');

		$('.pre-img').removeClass('pre-img');
		$(imgDoms[pre]).addClass('pre-img');

		$('.next-img').removeClass('next-img');
		$(imgDoms[next]).addClass('next-img');
	})
	setInterval(function() {
        $("#next").trigger("click");
    }, 5000);
	
})