var page_num  = 2;//当前页面
       var max_show_page = 10;//最多显示分页页数
       var max_page = 20;//总页面数
       //从第几页开始显示分页信息
	var start_page = (page_num - Math.ceil(max_show_page / 2));
	if (start_page < 1) {
	    start_page = 1;
	}
	//分页信息显示到第几页
	var end_page = page_num + max_show_page/2;
	if (end_page > max_page) {
	    end_page = max_page + 1;
	}
       for(var i=start_page;i < end_page;i++){
        //页码显示的代码
       }