4：垂直水平居中 

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>垂直水平居中</title>
  </head>
  <style>
    /* .box {
      width: 500px;
      height: 500px;
      background-color: pink;
      display: grid;
    } */
    /* .box {
      width: 500px;
      height: 500px;
      background-color: pink;
      position: relative;
    } */
    /* .box {
      width: 500px;
      height: 500px;
      background-color: pink;
      display: flex;
      justify-content: center;
      align-items: center;
    } */
    /* .modal {
      width: 50px;
      height: 50px;
      background-color: forestgreen;
      position: absolute;
      margin: auto;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
    } */
    /* .modal {
      width: 50px;
      height: 50px;
      position: absolute;
      left: 50%;
      top: 50%;
      margin-left: -25px;
      margin-top: -25px;
      background-color: green;
    } */
    /* .modal {
      position: absolute;
      left: 50%;
      top: 50%;
      transform: translate(-50%, -50%);
      background-color: green;
    } */
    /* .modal {
      background-color: green;
      align-self: center;
      justify-self: center;
    } */
  </style>
  <body>
    <section class="box">
      <div class="modal">1232112312312321311231313</div>
    </section>
    <script>
      let first = `子元素宽高固定的情况:宽高一半；2利用margin auto`;
      let second = `利用margin auto`;
      let third = `子元素宽高未知的情况`;
      let fourthly = `flex布局`;
      let fifth = `grid布局`;
    </script>
  </body>
</html>

 

posted @ 2022-04-25 18:22  苹果π  阅读(19)  评论(0)    收藏  举报