JSFiddle - React, Tailwind, and code Playground

by wimp9487

HTML

simple counter:
<button onClick="minus()">-</button>
<button onClick="plus()">+</button>
<hr>

simple calculator:
<input class="firstNumber" type="number" />
<input class="secondNumber" type="number" />
<button onClick="allValue()">加/減/乘/除</button>

JavaScript

let n = 0;

const minus = () => {
   n--;
   alert(n);
}
const plus = () => {
   n++;
   alert(n);
}
let firstInput = document.querySelector('.firstNumber');
let secondInput = document.querySelector('.secondNumber');
const allValue = () => {
  let firstValue = parseInt(firstInput.value);
  let secondValue = parseInt(secondInput.value);
  alert(firstValue + secondValue);
  alert(firstValue - secondValue);
  alert(firstValue * secondValue);
  alert(firstValue / secondValue);
}