要產生該紅圈圈 方法有三: <i style="width:20px;height:20px;border-radius:50%;background-color:red;display: block"></i> <div style="width:20px;height:20px;border-radius:50%;background-color:red;"></div> <span style='color:red;'>●</span>
參考網址:https://www.cnblogs.com/xianfengzhike/p/9461955.html