var flash_t = null;
var flash_time = 3000;
var flash_height = null;
var flash_n = 1;
var flash_index = null;
$(function(){
	flash_height = $(".mian_flash_index").height();
	if($(".mian_flash_index li").length > 1){
		var flash_html = "";
		$(".mian_flash_index li").each(function(i){//动态增加按钮个数
			  if(i == 0){
				  flash_html = "<span class=\"shownums shownumsselected\">"+(i+1)+"</span>";
			  }else{
				  flash_html += "<span class=\"shownums\">"+(i+1)+"</span>";
			  }
		  });
		flash_html = "<div class=\"shownum\">"+flash_html+"</div>";//在幻灯区域内创建按钮
		$(".mian_flash_index").append(flash_html);
		$(".mian_flash_index").hover(function(){//鼠标移上去停止切换
			clearInterval(flash_t);
	  	}, function(){
			flash_t = setInterval(function(){
				startmarquee();
			},flash_time);
		});
		$(".shownum .shownums").click(function(){//鼠标移到数字
			flash_index = $(".shownums").index(this) + 1;
			startmarquee();
		  });
		$(".shownum .shownums").mouseout(function(){//防止点击后出现错误
			clearInterval(flash_t);
		});
		startmarquee();
	}
});
function startmarquee(){
	clearInterval(flash_t);
	if(flash_index != null){//判断是否是有点击按钮
		flash_n = flash_index;
	}
    $(".mian_flash_index .ul").animate({//图片切换
		"margin-top":-flash_height*(flash_n-1)
	},"slow");
	$(".shownum .shownums").eq(flash_n-1).addClass("shownumsselected").siblings().removeClass("shownumsselected");//图片切换后给当前按钮改变class
	flash_index = null;//恢复初始化点击按钮
	if(flash_n >= $(".mian_flash_index li").length){//设置下一个切换的项目
		flash_n = 1;
	}else{
		flash_n = flash_n + 1;
	}
  flash_t = setInterval(function(){//超时执行
	  startmarquee();
  },flash_time);
}