I am trying do arithmetic operation using radio button (just an experiment)
browser returns value NaN
let num1 = parseInt(document.querySelectorAll('#number1:checked'));
let num2 = parseInt(document.querySelectorAll('#number2:checked'));
function addTambah() {
result = num1 + num2;
alert(result);
}<p>number : </p>
<input type="radio" name="number1" id="number11" value="1">
<label for="radio">1</label>
<input type="radio" name="number1" id="number12" value="2">
<label for="radio">2</label>
<p> number 2 : </p>
<input type="radio" name="number2" id="number21" value="1">
<label for="radio">1</label>
<input type="radio" name="number2" id="number22" value="2">
<label for="radio">2</label>
<br>
<button type="button" onclick="addTambah()">Add</button>You need to get the value of the checked radio buttons inside the function & secondly every dom element should have unique id. Also use querySelector instead of querySelectorAll
function addTambah() {
let add = document.querySelector('input[name="number1"]:checked').value;
let add1 = document.querySelector('input[name="number2"]:checked').value;
const result = parseInt(add, 10) + parseInt(add1, 10)
alert(result);
}<p>number : </p>
<input type="radio" checked name="number1" id="number1" value="1">
<label for="radio">1</label>
<input type="radio" name="number1" id="number2" value="2">
<label for="radio">2</label>
<p> number 2 : </p>
<input type="radio" name="number2" id="number3" value="1">
<label for="radio">1</label>
<input type="radio" checked name="number2" id="number4" value="2">
<label for="radio">2</label>
<br>
<button type="button" onclick="addTambah()">Add</button>