栅格布局的两种简单的实现方式

使用float：

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title></title>
  <style>
      section
      {
        border: solid 1px;
      }
      section section
      {
        float: left;
        margin-left: 10px;
        margin-top: 10px;
        text-align: center;
        width: 200px;
        border-radius: 20px;
        height: 200px;
      }
      .parent
      {
        height: 440px;
        width: 660px;
      }
      .parent section:first-child
      {
        height: 410px;
      }
  </style>
</head>
<body>
  <section class="parent">
    <section>A</section>
    <section>B</section>
    <section>C</section>
    <section>D</section>
    <section>E</section>
  </section>

</body>
</html>

使用display：flex（这个css3属性仅谷歌和火狐支持）

<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title></title>
  <style>
      section
      {
        border: solid 1px;
      }
      section section
      {
        margin-left: 10px;
        margin-top: 10px;
        text-align: center;
        width: 200px;
        border-radius: 20px;
        height: 200px;
      }
      .parent
      {
        display: flex;
        flex-direction: column;
        flex-wrap: wrap;
        height: 440px;
        width: 660px;
      }
      .parent section:first-child
      {
        height: 410px;
      }
  </style>
</head>
<body>
  <section class="parent">
    <section>A</section>
    <section>B</section>
    <section>C</section>
    <section>D</section>
    <section>E</section>
  </section>

</body>
</html>

实现效果如图所示：

当然使用table和负边距也是可以实现的，有时间补上:-D