console 命令行工具 X clear

console

<html>
  <body>
    <div class="page">
      <main>
        1212121111111111111111111111111111111
      </main>
      <footer></footer>
    </div>
  </body>
</html>

body, html {
  width: 100%;
  height: 100%;
}
.page {
  min-height: 100%;  
  position: relative;
  background: blue;
}
footer {
  height: 20px;
  width: 100%;
  background: red;
  position: absolute;
  bottom: 0;
}