js实现交通灯效果的教程

#traffic>li{

      display:block;

      }

    #traffic span{

      display:inline-block;

      width:50px;

      height:50px;

      background-color:gray;

      margin:5px;

      border-radius:50%;

      float:left;

    }

    #traffic.stop li:nth-child(1) span{

      background-color:yellow;

    }

    #traffic.waitli:nth-child(2) span{

      background-color:red;

    }

    #traffic.pass li:nth-child(3) span{

      background-color:green;

    }

const traffic = document.getElementById("traffic");

(functionreset(){

  traffic.className ="wait";

  setTimeout(function(){

    traffic.className ="stop";

    setTimeout(function(){

      traffic.className ="pass";

      setTimeout(reset,2000);

    },2000);

  },2000);

})();