JSFiddle - React, Tailwind, and code Playground

by superyngo

HTML

simple counter:
<button>-</button>
<button>+</button>

<hr>

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

JavaScript

const app1MinusBtn=document.querySelectorAll("button")[0]
const app1PlusBtn=document.querySelectorAll("button")[1]
const app2evalBtn=document.querySelectorAll("button")[2]


app1MinusBtn.onclick=app1Minus
app1PlusBtn.onclick=app1Plus
app2evalBtn.onclick=app2Eval

let app1result=0

function app1Plus(){
	app1result = app1result +1
  alert(app1result)
}

function app1Minus(){
	app1result = app1result -1
  alert(app1result)
}

function app2Eval(){
  const num1 =parseFloat(document.querySelectorAll("input")[0].value)
  const num2 =parseFloat(document.querySelectorAll("input")[1].value)
  alert(num1+num2)
  alert(num1-num2)
  alert(num1*num2)
  alert(num1/num2)

}