這個問題在這里已經有了答案： querySelectorAll 和 getElementsBy* 方法回傳什么？ (10 個回答) 2 天前關閉。
我正在嘗試使用單選按鈕進行算術運算（只是一個實驗）
瀏覽器回傳值 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>uj5u.com熱心網友回復：
您需要獲取函式內選中的單選按鈕的值，其次每個 dom 元素都應該具有唯一的 id。也用querySelector代替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>轉載請註明出處，本文鏈接：https://www.uj5u.com/shujuku/375204.html
標籤：javascript html dom