JSFiddle - React, Tailwind, and code Playground

by RomanFF

HTML

<input type="text" value = ''>
<p> = </p>

<input type = 'submit' value = '*' class = 'operator'>
<input type = 'submit' value = '+' class = 'operator'>
<input type = 'submit' value = '/' class = 'operator'>
<input type = 'submit' value = '-' class = 'operator'>

<button>посчитать</button>

JavaScript

let input = document.querySelector('input');
let resultBtn = document.querySelector('button');
let p = document.querySelector('p');
let operator = document.querySelectorAll('.operator')
console.log(operator)

resultBtn.addEventListener('click', multiply);

function multiply() {
  let str = input.value + 'ope';
  let arr = String(str).split('*');
  p.innerHTML += arr[0] * arr[1];
}

for (let i = 0;i<operator.length; i++){
	operator[i].addEventListener('click', addOperator);
}


function addOperator() {
  if (input.value.length > 0) {
    input.value += this.value[this.value.length - 1];
  }
}