技術標籤：javascriptcssjs

<div class="box">
        <div class="green"></div>
        <div class="red"></div>
        <div class="yeoolw"></div>
    </div>
    <div class="gz"></div>

   *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 100px;
            height: 50px;
            display: flex;
            justify-content: center;
            align-items: center;
            background-color: darkgray;
            margin-top: 200px;
            margin-left: 100px;
        }
        .green{
            width: 30px;
            height: 30px;
            margin: 5px;
            background: darkgreen;
            border-radius: 50%;
            opacity: 0.3;

        }
        .red{
            width: 30px;
            height: 30px;
            margin: 5px;
            border-radius: 50%;
            background: red;
            opacity: 0.3;
        }
        .yeoolw{
            width: 30px;
            height: 30px;
            margin: 5px;
            border-radius: 50%;
            background: yellow;
            opacity: 0.3;
        }
        .gz{
            width: 20px;
            height: 150px;
            position: relative;
            background: darkgray;
            top:1px;
            left: 100px;
           
        }
        .light{
            opacity: 1;
        }
 

            function x(){
         r_1()//紅燈亮
        setTimeout(y_1, 1000);//黃燈一秒後亮
        setTimeout(r_1, 1000);//黃燈亮的同時關閉紅燈
        setTimeout(g_1, 2000);//綠燈兩秒後亮
        setTimeout(y_1, 2000);//綠燈亮，黃燈熄
        setTimeout(g_1, 3000);//三秒後，紅燈熄
         
          
        }
      

        function r_1(){
            var
 
 r=document.querySelector('.red');
            r.classList.toggle('light');
        }
        function g_1(){
            var g=document.querySelector('.green');
            g.classList.toggle('light');
        }
        function y_1(){
            var y=document.querySelector('.yeoolw');
            y.
 
classList.toggle('light');
        }
       
     
       x();
       window.onload = function () {
        t1 = setInterval(x, 3000)//每隔三秒重複執行函式
  };

比較簡單吧，就是通過 setTimeout,然後通過toggle切換一下樣式，自我感覺重複率太高，值得優化一下程式碼