js实现图片淡入淡出效果

Setz_index:function(){
        for(var i=0;i<this.Photo.length;i++ ){
            index=i;
            this.Photo[i].style.zIndex =this.Photo.length-i-1;
        }
    },

Animatezindex:function(math,count){
       for(var i=0;i<count;i++){
         for(var k=0;k<this.Photo.length;k++) {
            //console.log(1);
           var index=parseInt (this.Photo[k].style.zIndex );  //43210  04321 10432
           if(math=="n"){
             index++;    //小点从左向右变化颜色
             if(index ==this.Photo.length){
                 index=0;
                 this.Photo[k].style.opacity =0;
                 this.Crclelist [k].style.background ="#fff";
             }
             if(index==this.Photo.length-1){
                 this.Photo [k].style.opacity= 1;
                 this.Crclelist [k].style.background ="pink";
                 this.Savecolor= this.Crclelist [k];

             }
           }
             else{
               index--;   //小点从右向左变化颜色
               if(index==-1){
                   index=this.Photo.length-1;
               }
               if(index==this.Photo.length-1){
                   this.Photo [k].style.opacity= 1;
                   this.Crclelist [k].style.background ="pink";
                   this.Savecolor= this.Crclelist [k];
               }
               if(index==this.Photo.length-2){
                   this.Photo[k].style.opacity =0;
                   this.Crclelist [k].style.background ="#fff";
               }
           }
             this.Photo[k].style.zIndex =index;
         }
       }
    },

Moren_set:function(){
        var that=this;
        that.Crclelist [0].style.background ="pink";
        that.Savecolor =that.Crclelist[0];
        that.Bigblock.onmouseenter=function(){
            //  console.log(1);
            window.cancelAnimationFrame ( glider.Timeset);
        };
        that.Bigblock.onmouseleave=function(){
            glider.Timelines();
        }
        //点的事件，跟随图片变化
        for(var i=0;i<that.Crclelist.length;i++){
            that.Crclelist[i].index=i;
            that.Crclelist[i].onmouseenter =function(){
              var oldindex=that.Savecolor.index;
              var newindex=this.index;  //鼠标滑进的圆点的索引 this指的是当前的圆点的滑动事件
 //               console.log(newindex);
                if(newindex -oldindex >0) {   //从当前圆点的右边进
                  var ri=newindex -oldindex;
                  //  console.log(ri);
                    var le= that.Crclelist.length-ri;
                   // console.log(le);
                    if(ri<=le){
                        console.log("向右",ri);
                        that.Animatezindex("n",ri);
                    }
                    if(ri>le){
                        console.log("向左",le);
                        that.Animatezindex("s",le);
                    }
                }
                else if(newindex -oldindex<0){
                    var ri1=Math.abs(newindex-oldindex)   ; //取绝对值
                    var le1=that.Crclelist.length-ri1;
                    if(ri1<=le1){
                        console.log("向左", ri1);
                        that.Animatezindex("s",ri1);
                    }
                    if(ri1>le1){
                        console.log("向右", le1);
                        that.Animatezindex("n",le1);
                    }

                }
            }
        }
    }

Timelines:function(){
        var nowtime=new Date().getTime ();
        if((nowtime -glider.Oldtime) >=glider.TimeDely ){
            glider.Oldtime =nowtime;
            glider.Animatezindex ("n",1);  //向 右变化
        }
        //可以通过setTimeout和setInterval方法来在脚本中实现动画，
        // 但是这样效果可能不够流畅，且会占用额外的资源。
        //requestAnimationFrame方法用于通知浏览器重采样动画,循环播放。
        
       glider.Timeset =window.requestAnimationFrame(glider.Timelines);
 }