<div class="banner">

		<div class="ban"></div>

		<ul class="ban_bar">

			<li><a href="" img="images/banner.jpg"><img src="images/banner_dadian.png" alt=""></a></li>

			<li><a href="" img="images/banner2.jpg"><img src="images/banner_xiaodian.png" alt=""></a></li>

			<li><a href="" img="images/banner3.jpg"><img src="images/banner_xiaodian.png" alt=""></a></li>

			<li><a href="" img="images/banner4.jpg"><img src="images/banner_xiaodian.png" alt=""></a></li>

		</ul>

	</div>

function banner_start(){

	function changeImg(){

		var strPath = arguments[0];

		$(".banner").css("background","url("+ strPath +") center");

		$(".banner .ban").fadeOut("slow",function(){

			$(".banner .ban").css("background","url("+ strPath +") center");

			$(".banner .ban").show();

		});

	}

	$(".banner li a").click(function(){

		changeImg($(this).attr("img"));

		$(".banner li a img").attr("src","images/banner_xiaodian.png");

		$(this).find("img").attr("src","images/banner_dadian.png");

		return false;

	});

	var i = 1;

	setInterval(function(){

		$(".banner li a")[i].click();

		i++;

		i = i % 4;

	},2000);

	$(".banner li a")[0].click();

}