Прокрутить страницу не на 100px а на 100vh

<button onclick = 'window.scrollBy(0, window.innerHeight)'>window.scrollBy(0, window.innerHeight)</button>

$("#scroll").click(function() { 
  $('body').animate({ scrollTop: '+=' + window.innerHeight }, 'slow'); 
});

.area { 
  height: 200px; 
  margin-top: 10px; 
  background-color: black; 
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> 
<button id="scroll">scroll</button> 
<div class="area"></div> 
<div class="area"></div> 
<div class="area"></div> 
<div class="area"></div> 
<div class="area"></div>