$.fn.jqslider = function() {
    var fun = function(parentobj){
        var pictotal = parentobj.find('.list-box li').length; //总共几张
        var currentindex = 0; // 当前要显示的索引
        var todisplaypicnumber = 1; // 定时器下一次执行用到的索引
        var timer = null; // 定时器对象
        var hideindex = 0; // 要隐藏的索引
        var itime = 6000; // 间隔时间

        //插入html代码
        var speedhtml = '<div class="speed-box"><div class="speed-btn">';
        for(var i=0; i<pictotal; i++){
            speedhtml += '<a href="javascript:;"></a>';
        }
        speedhtml += '</div></div>';
        $(speedhtml).appendto(parentobj); //插入进度按钮
        $('<a class="prev-btn" href="javascript:;"></a><a class="next-btn" href="javascript:;"></a>').appendto(parentobj); //插入左右按钮
        parentobj.find('.list-box li').eq(0).css({'opacity':1,'z-index':2});
        parentobj.find('.speed-btn a').eq(0).addclass('selected');
        
        //移上移下显示隐藏
        parentobj.hover(function(){
        	cleartimeout(timer);
            parentobj.find('.prev-btn').show();
            parentobj.find('.next-btn').show();
        },function(){
        	parentobj.find('.prev-btn').hide();
            parentobj.find('.next-btn').hide();
        	timer = settimeout(picnumclick, itime);
        	//离开从新赋值
        	todisplaypicnumber = (currentindex + 1 == pictotal ? 0 : currentindex + 1);
        });
        //下一个
        parentobj.find('.next-btn').click(function(){
        	currentindex = (currentindex + 1 == pictotal ? 0 : currentindex + 1); 
        	displaypic();
        });
        //上一个
        parentobj.find('.prev-btn').click(function(){
        	currentindex = (currentindex - 1 < 0 ? pictotal-1 : currentindex -1); 
        	displaypic();
        });
        //中间按钮
        parentobj.find('.speed-btn a').click(function(){
        	currentindex = $(this).index();
        	displaypic();
        });
        
        //图片切换效果
        function displaypic() {
            cleartimeout(timer);
			if(currentindex == hideindex){return;}
            parentobj.find('.list-box li').eq(currentindex).css({'opacity':1,'z-index':2});
            parentobj.find('.list-box li').eq(hideindex).css({'z-index':5}).stop(true,true).animate({'opacity':0}, 300 , function(){
            	hideindex = currentindex;
            	$(this).css({'z-index':1});
            });
            parentobj.find('.speed-btn a').eq(currentindex).addclass('selected').siblings().removeclass('selected');
        }
        //循环调用自身
        function picnumclick() {
            parentobj.find(".speed-btn a").eq(todisplaypicnumber).trigger("click");
            todisplaypicnumber = (todisplaypicnumber + 1) % pictotal;
            timer = settimeout(picnumclick,itime);
        }
        settimeout(picnumclick, itime);
	};
	return $(this).each(function() {
		fun($(this));						 
	});
}