JSFiddle - React, Tailwind, and code Playground

HTML

<div id="counter">
  <button type="button" data-action="decrement" onClick="decrement();">-1</button>
  <span id="value">0</span>
  <button type="button" data-action="increment" onClick="increment();">+1</button>
</div>

JavaScript

var counterValue = 0;
function increment(){
	counterValue +=1;
  document.getElementById('value').innerHTML = counterValue;
}
function decrement(){
	counterValue -=1;
  document.getElementById('value').innerHTML = counterValue;
}