How To Calculate 2 Numbers Using Javascript

How To Calculate 2 Numbers Using Javascript, add and subtract multiply and divide two numbers with Javascript.

Bài tập làm phép toàn cộng, trừ, nhân, chia hai số bằng Javascript

1. Javascript

<script>

  function mycalc() {

    var x = Number(document.getElementById('txt1').value);

    var y = Number(document.getElementById('txt2').value);

    var op = document.getElementById('option').value;

    if (op === '+') {

      document.getElementById('result').innerHTML = x + y;

    }

    if (op === '-') {

      document.getElementById('result').innerHTML = x - y;

    }

    if (op === '/') {

      document.getElementById('result').innerHTML = x / y;

    }

    if (op === 'x') {

      document.getElementById('result').innerHTML = x * y;

    }

  }

</script>

2. HTML

<p>Number 1: <input type="text" id="txt1" /></p>

<p>Number 2: <input type="text" id="txt2" /></p>

<select id="option" style="width:50px">

  <option value="+">+</option>

  <option value="-">-</option>

  <option value="/">/</option>

  <option value="x">x</option>

</select>

<button onclick="mycalc();">=</button>

<span id='result'></span>

3. Demo

Number 1:

Number 2:

+ - / x