js+css3手风琴展开收缩下拉菜单代码

js代码

<script>
var list = document.querySelectorAll('.list');

function accordion(e) {
    e.stopPropagation();
    if (this.classList.contains('active')) {
        this.classList.remove('active');
    } else
    if (this.parentElement.parentElement.classList.contains('active')) {
        this.classList.add('active');
    } else
    {
        for (i = 0; i < list.length; i++) {
            list[i].classList.remove('active');

        }
        this.classList.add('active');
    }
}
for (i = 0; i < list.length; i++) {
    list[i].addEventListener('click', accordion);
}
</script>