Vanilla JS - 可以在子元素上 add/remove class 但所有元素都处于活动状态

Question

我可以在子元素上添加和删除类，但所有元素都处于活动状态。我试图一次仅在一个活动元素上添加和删除。我错过了什么？

<ul id="parent" class="container">
  <li class="child"><a href="#one">one</a></li>
  <li class="child"><a href="#two">two</a></li>
  <li class="child"><a href="#three">three</a></li>
</ul>


document.addEventListener("DOMContentLoaded", function() {

  const parent = document.querySelector('#parent');
  parent.style.backgroundColor = 'blue';
  const childrens = document.querySelectorAll('.child');
  const child = document.querySelector('.child a')

  Array.prototype.forEach.call(
   document.querySelectorAll('.child'),
    function(element) {
      element.onclick = addActive;
    }
  );

 function addActive(element){
  element = this;
   if(element.classList.contains('active')) {
    element.classList.remove('active');
   } else {
    element.classList.add('active');
   }
 }
});

这是一个：codepen

Answer 1

现在您 adding/removing 仅来自被点击元素的活动 class。在将单击的元素设置为活动元素之前，您必须从所有元素中删除 class。

例如

function addActive(element) {
  element = this;
  if (element.classList.contains('active')) {
    element.classList.remove('active');
  } else {
    childrens.forEach(function(e) {
      e.classList.remove('active');
    });
    element.classList.add('active');
  }
}

Answer 2

一个解决方案是先从所有元素中删除 active class：

function addActive(element) {

  childrens.forEach(function(elem) {
    elem.classList.remove("active");
  });

  element = this;
  if (element.classList.contains("active")) {
    element.classList.remove("active");
  } else {
    element.classList.add("active");
  }
}

这里是working Codepen example.

Answer 3

这可能是使用纯 js 切换子元素的最直接方法。

<ul id="parent" class="container">
 <li class="child"><a href="#one">one</a></li>
 <li class="child"><a href="#two">two</a></li>
 <li class="child"><a href="#three">three</a></li>
</ul>

<script>
//get children 
var theChildren = document.querySelector('#parent').children;

//set event listener for to each child
function selectChild(child) {
child.addEventListener('click', function() {
    var checkChildStatus = document.querySelector('#parent .selected');
    if (checkChildStatus) {
        checkChildStatus.classList.remove('selected');
    }
    
    child.classList.add('selected');        
 });
}

//loop through all children
[...theChildren].forEach(selectChild);
</script>

Vanilla JS - 可以在子元素上 add/remove class 但所有元素都处于活动状态

Vanilla JS - Can add/remove class on child elements but all are active

javascript

events

children