JSFiddle - React, Tailwind, and code Playground

by Serhii Matrunchyk

HTML

<input value="0" type="number">
<button>+</button>
<div>
  Result: <span>0</span>
</div>

JavaScript

const btn = document.querySelector('button');
let result = 0;

btn.addEventListener('click', calculate);

function calculate() {
  const inp = document.querySelector('input');
  const val = Number(inp.value);
  const span = document.querySelector('span');

	result = result + val;
  inp.value = 0;
  span.textContent = result;
}