JSFiddle - React, Tailwind, and code Playground

HTML

<div id="c"></div>
<button id="btn">left</button>
<button id="btn1">right</button>

CSS

#c {
  width: 100px;
  height: 100px;
  background: black;
}

JavaScript

var block = document.getElementById('c');
var buttR = document.getElementById('btn');
var buttL = document.getElementById('btn1');
var posX = 0;
var val = 0;

function updateMargin(x) {
	block.style.marginLeft = x + '%';
}
buttL.onclick = function () {
  posX++;
  updateMargin(posX);
}
buttR.onclick = function () {
  posX--;
  updateMargin(posX);
}