JSFiddle - React, Tailwind, and code Playground

by evon0306

HTML

simple counter:
<button id="minus">-</button>
<button id="add">+</button>

<hr>

simple calculator:
<input id="num1" type="text" />
<input id="num2" type="text" />
<button id="result">加/減/乘/除</button>

JavaScript

const minusBtn = document.querySelector('#minus');
const addBtn = document.querySelector('#add');
const resultBtn = document.querySelector('#result');

let sum = 0;
minusBtn.onclick = () =>{
   sum--;
   alert(sum);
}
addBtn.onclick = () =>{
   sum++;
   alert(sum);
}

resultBtn.onclick = ()=> {
   let num1 = Number(document.querySelector('#num1').value);
   let num2 = Number(document.querySelector('#num2').value);
   console.log(num1);
   console.log(num2);
   alert(num1 + num2);
   alert(num1 - num2);
   alert(num1 * num2);
   alert(num1 / num2);
}