JSFiddle - React, Tailwind, and code Playground

HTML

<p>
  <input type=button id=up value="jump up" />
</p>
<p>
  <input type=button id=down value="jump down" />
</p>

JavaScript

var prevVal = 0; 
var currentVal = 0;

function jump(howHigh){ 
    prevVal = currentVal; 
    currentVal = currentVal + howHigh; 
    $("<p>").text(currentVal).appendTo(document.body)
}

$("#up").click(function(){jump(1)})
$("#down").click(function(){jump(-1)})