<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js"></script>

<style>
.floating {
  position: absolute;
  bottom: -50px;
  left: 50%;
  margin-left: -100px;
  z-index: 1;
}
</style>

<div class="floating">
  <p>浮动层的内容</p>
</div>