<style>
    div:first-child {
      width: 300px;
      height: 50px;
      background-color: red;
      color: white;
      margin: 20px auto;
      text-align: center;
      line-height: 50px;
    }

    div:nth-child(2) {
      position: relative;
      width: 300px;
      height: 50px;
      margin: 100px auto;
    }
    input {
      width: 300px;
      height: 46px;
      border: 0px white;
      border-bottom: 1px solid black;
      outline: none;
    }
    #eyes {
      width: 18px;
      position: absolute;
      top: 27px;
      right: 2px;
    }
  </style>

 <div>
    密码
  </div>
  <div>
    <input type="password">
    <!--默认闭眼图-->
    <label><img src="/UploadFiles/2021-04-02/1.png">

 
js部分


<script>
      //获取元素（两种方式都可以）
    var input = document.querySelector('input')
    var imgs = document.getElementById('eyes');
    //下面是一个判断每次点击的效果
    var flag = 0;
    imgs.onclick = function () {
      if (flag == 0) {
        input.type = 'text';
        eyes.src = '2.png';//睁眼图
        flag = 1;
      } else {
        input.type = 'password';
        eyes.src = '1.png';//闭眼图
        flag = 0;
      }
    }
  </script>


总结