Allenice/height-equal-width.html

## height-equal-width.html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    .h-equal-w {
      width: 100px;
      overflow: hidden;
      background: #ccc;
      position: relative;
    }

    .h-equal-w:before {
      content: '';
      display: block;
      padding-top: 100%;
    }

    .content {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
    }

  </style>
</head>
<body>
  <div class="h-equal-w">
    <div class="content">height equal width</div>
  </div>
</body>
</html>