<div class="demo-content" id="content">
  <a href="#" class="icon down" id="go-down">
    <span class="text">Scroll Down</span>
    <span class="ion ion-arrow-down-c"></span>
  </a>
  <div class="inner-content">
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Fugiat eum quas in, cumque, quibusdam quos tempora inventore reprehenderit delectus soluta maxime veniam quam ea vero sed alias saepe possimus provident.</p>
    <p><img src="" alt="" /></p>
  </div>
  <a href="#" class="icon up" id="go-up">
    <span class="ion ion-arrow-up-c"></span>
    <span class="text">Scroll Up</span>
  </a>
</div>

body {
  background-color: #F5F7FA;
}
.demo-content {
  position: relative;
  padding: 70px 20px;
  height: 1500px;
}
.inner-content {
  font-family: "Roboto", Arial, sans-serif;
  margin-top: 50px;
  width: 500px;
  margin-right: auto;
  margin-left: auto;
  color: #6c6f73;
  text-align: center;
  font-weight: 300;
}
.text {
  display: block;
  margin: 10px 0;
  color: #6c6f73;
  text-transform: uppercase;
  font-family: "Roboto", Arial, sans-serif;
}
.ion {
  -webkit-font-smoothing: antialiased; 
  -moz-osx-font-smoothing: grayscale;
  font-size: 18px;
  display: block;
  width: 32px;
  height: 32px;
  line-height: 1.8;
  border-radius: 50%;
  border: 1px solid #CCD1D9;
  margin-right: auto;
  margin-left: auto;
}
.icon {
  color: #434A54;
  text-decoration: none;
  display: block;
  margin-right: 5px;
  text-align: center;
  width: 120px;
  position: absolute;
  left: 50%;
  margin-left: -60px;
  font-size: 11px;
}
.down {
    top: 10px;
    margin-top: 20px;
}
.up {
    bottom: 10px;
    margin-bottom: 20px;
}
.ion {
  background-color: #fff;
  box-shadow: 1px 1px 0 0 rgba(0,0,0,0.1);
}

var $down = $("#go-down");
var $up = $("#go-up");

$down.on("click", function() {
  $up.velocity("scroll", { 
    duration: 2000,
    easing: "easeInBack"
  });
});

$up.on("click", function() {
  $("body").velocity("scroll", { 
    duration: 2000,
    easing: "easeInBack"
  });
});