JS 複選框 全選 判斷複選框是否全選
html 代碼
<input type="checkbox" name="all" id="all">全選
<hr>
<input type="checkbox" name="check_item">
<hr>
<input type="checkbox" name="check_item">
<hr>
<input type="checkbox" name="check_item">
<hr>
<input type="checkbox" name="check_item">
<hr>
JS 代碼
const allCheck = document.querySelector('#all')
const check_item = document.querySelectorAll("input[name='check_item']")
allCheck.addEventListener('click', () => {
if (!allCheck.checked) return check_item.forEach(v => v.checked = false);
check_item.forEach(v => v.checked = true)
});
let count = 0;
check_item.forEach(v => {
v.addEventListener('click', _ => {
v.allCheck ? ++count : --count
if (count == check_item.length) allCheck.checked = true
else allCheck.checked = false
})
})