HTML元素居中 - 技术栈

⾏内元素⽔平垂直居中设置⽗级标签。⽔平居中： text-align: center 垂直居中： line-height：盒⼦⾼度

⽔平垂直都居中

<!DOCTYPE html>
<html>
<head>
  <style>
    .container {
      position: relative;
      width: 200px;
      height: 200px;
      border: 1px solid black;
    }

    .child {
      position: absolute;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      width: 100px;
      height: 100px;
      background-color: blue;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="child"></div>
  </div>
</body>
</html>

top: 50%;

left: 50%;

transform: translate(-50%, -50%);

这三个需要一起用实现居中

绝对定位 + 四个方向 margin: auto

<!DOCTYPE html>
<html>
<head>
  <style>
    .container {
      position: relative;
      width: 200px;
      height: 200px;
      border: 1px solid black;
    }

    .child {
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      margin: auto;
      width: 100px;
      height: 100px;
      background-color: blue;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="child"></div>
  </div>
</body>
</html>

top: 0;

left: 0;

right: 0;

bottom: 0;

margin: auto;这5个需要一起用

flex 布局

<!DOCTYPE html>
<html>
<head>
  <style>
    .container {
      display: flex;
      justify-content: center;
      align-items: center;
      width: 200px;
      height: 200px;
      border: 1px solid black;
    }

    .child {
      width: 100px;
      height: 100px;
      background-color: blue;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="child"></div>
  </div>
</body>
</html>

display: flex;

justify-content: center;

align-items: center;这三个需要一起用

table-cell

<!DOCTYPE html>
<html>
<head>
  <style>
    .container {
      display: table-cell;
      text-align: center;
      vertical-align: middle;
      width: 200px;
      height: 200px;
      border: 1px solid black;
    }

    .child {
      width: 100px;
      height: 100px;
      background-color: blue;
    }
  </style>
</head>
<body>
  <div class="container">
    <div class="child"></div>
  </div>
</body>
</html>

display: table-cell;

text-align: center;

vertical-align: middle;这三个需要一起用