SOURCE

console 命令行工具 X clear

                    
>
console
$('.box').hover(function () {
      $('.show').show()
  })
  $('.show').click(function () {
      $(this).toggle()
  })
<div class="box">
    <button>hover</button>
    <div class="show"></div>
</div>
.box{
            width: 100%;
            height: 50px;
            position: relative;
            line-height: 50px;
        }
        .show{
            width: 100%;
            height: 50px;
            background: red;
            position: absolute;
            left: 0;
            top: 50px;
            display: none;
        }