$(function(){
	/*未元素的首尾添加补白*/
	var $panels				= $('#slider .scrollcontainer > li');
	var $parent=$panels.parent();//或许当前li的最近一级的父元素
	var $length=$panels.length;//获取指定length值
	var $first=$panels.eq(0).clone().addclass("panel cloned").attr("id",'panel_'+($length+1));//获取第一个元素并复制
	var $last=$panels.eq($length-1).clone().addclass("cloned").attr("id",'panel_0');;//获取最后一个元素并复制
	$parent.append($first);//将li序列中的第一个添加到ul元素中的最后一个  $("#slide02").scrollleft(0);
	$parent.prepend($last);//将li序列中的最后一个添加到ul元素中的第一个
	var totalpanels			= $(".scrollcontainer").children().size();//所有子元素的数字，滚动元素的个数 7
	var regwidth			= $(".panel").css("width");//获取li元素的宽度
	var regimgwidth			= $(".panel img").css("width");//获取其中图片的宽度
	var movingdistance	    = 310;//每次移动的距离
	var curwidth			= 380;//当前中间li的宽度为350px
	var curheight         =260;//当前中间li的高度未312  
	var curimgwidth  =380;
	var curimgheight  =260;
	var othersw           =290;//其他li的宽度
	var othersh           =198;//高度
	var othersimgw           =290;//其他li的宽度
	var othersimgh           =198;//高度
	var $panels				= $('#slider .scrollcontainer > li');//此处作用是将复制进来补白的元素重新赋值
	var $container			= $('#slider .scrollcontainer');
	$panels.css({'float' : 'left','position' : 'relative'});
	$("#slider").data("currentlymoving", false);//是否正在运动中
	$container.css('width', (($panels[0].offsetwidth+30) * $panels.length) + 60 ).css('left','0');//计算容器的总的宽度 ps：25为margin值 offsetwidth
	var scroll = $('#slider .scroll').css('overflow', 'hidden');
	function returntonormal(element) {//li元素返回到正常状态
		$(element).animate({ width: othersw,height: othersh}).find("img").animate({width:othersimgw,height:othersimgh});
	};
	function growbigger(element) {//当前元素之间变大
		$(element).addclass("current").animate({ width: curwidth,height:curheight}).siblings().removeclass("current")
		.end().find("img").animate({width:curimgwidth,height:curimgheight})
	}
	//direction true = right, false = left
	function change(direction) {
		//if not at the first or last panel
		if((direction && !(curpanel < totalpanels-2)) || (!direction && (curpanel <= 1))) {
			return false;
		}	
		//if not currently moving
		if (($("#slider").data("currentlymoving") == false)) {
			$("#slider").data("currentlymoving", true);
			var next         = direction ? curpanel + 1 : curpanel - 1;
			var leftvalue    = $(".scrollcontainer").css("left");
			var movement	 = direction ? parsefloat(leftvalue, 10) - movingdistance : parsefloat(leftvalue, 10) + movingdistance;
			$(".scrollcontainer").stop().animate({"left": movement}, function() {
				$("#slider").data("currentlymoving", false);
			});
			returntonormal("#panel_"+curpanel);
			growbigger("#panel_"+next);
			curpanel = next;
			//remove all previous bound functions
			$("#panel_"+(curpanel+1)).unbind();	
			//go forward
			$("#panel_"+(curpanel+1)).click(function(){ change(true); });
			//remove all previous bound functions															
			$("#panel_"+(curpanel-1)).unbind();
			//go back
			$("#panel_"+(curpanel-1)).click(function(){ change(false); }); 
			//remove all previous bound functions
			$("#panel_"+curpanel).unbind();
		}
	}
	// set up "current" panel and next and prev 设置当前元素和上下
	growbigger("#panel_1");	
	var curpanel = 1;
	$("#panel_"+(curpanel+1)).click(function(){ change(true);return false;});
	$("#panel_"+(curpanel-1)).click(function(){ change(false);return false;});
	//when the prev/next arrows are clicked
	$("#slider .next").click(function(){ change(true);});	
	$("#slider .prev").click(function(){ change(false);});
	$(window).keydown(function(event){//键盘方向键控制
		switch (event.keycode) {
			case 13: //enter
				$(".next").click();
			break;
			case 37: //prev arrow
				$(".prev").click();
			break;
			case 39: //next arrow
				$(".next").click();
			break;
		}
	});	
	
});