$(function() {
	var sWidth = $("#focus").width();
	var len = $("#focus ul li").length;
	var index = 0;
	var picTimer;
	var btn = "<div class='btnBg'></div><div class='btn'>";
	for(var i=0; i < len; i++) {
		btn += "<span></span>";
	}
	btn += "</div>";
	$("#focus").append(btn);
	$("#focus .btnBg").css("opacity",0.0);
	$("#focus .btn span").css("opacity",0.4).mouseenter(function() {
		index = $("#focus .btn span").index(this);
		showPics(index);
	}).eq(0).trigger("mouseenter");
	$("#focus ul").css("width",sWidth * (len));
	$("#focus").hover(function() {
		clearInterval(picTimer);
	},function() {
		picTimer = setInterval(function() {
			showPics(index);
			index++;
			if(index == len) {index = 0;}
		},4000); 
	}).trigger("mouseleave");
	function showPics(index) {
		var nowLeft = -index*sWidth; 
		$("#focus ul").stop(true,false).animate({"left":nowLeft},300);
		$("#focus .btn span").stop(true,false).animate({"opacity":"0.4"},300).eq(index).stop(true,false).animate({"opacity":"1"},300);
	}
});