Edit in JSFiddle

var button = $("#btn")

button.on("click", function() {
  var elm = $('.hoge')
  if (elm.is(':visible')) {
    elm.hide(100)
  } else {
    elm.show(100)
  }
})

<div>
  <button id="btn">Click Me</button>
</div>

<div class="hoge">
  hoge
</div>

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

button {
  background: #0084ff;
  border: none;
  border-radius: 5px;
  padding: 8px 14px;
  font-size: 15px;
  color: #fff;
}

.hoge {
  display: none;
  width: 100%;
  height: 10rem;
  background-color: #eb6ea5;
}