如何通过'role'属性选择元素并使用vanilla JS按类过滤？

Question

标记：

<ul>
  <li role="presentation" class="active">
    <a href="#1" aria-controls="1" role="tab">How to Install for iPad</a>
  </li>
  <li role="presentation">
    <a href="#2" aria-controls="2" role="tab">How to Install for Mac</a>
  </li>
  <li role="presentation">
    <a href="#3" aria-controls="3" role="tab">How to Install for PC</a>
  </li>
</ul>

当我使用document.querySelectorAll（'[role =“presentation”]'）; 结果是数组[li.active，li，li]

我如何删除.active类并使用普通JS w / o JQuery将其附加到这些li中的任何其他类更简单的方法？

Answer 1

尝试这个：

// remove active class from all elements
document.querySelectorAll('[role="presentation"]').forEach(function (el){
el.classList.remove("active");
});

// add class 'active' to last element
document.querySelectorAll('[role="presentation"]:last-of-type')[0].classList.add("active")

笔记：

• 'classList'在IE9中不起作用;
• 我认为您必须根据需要修改添加类行。

Answer 2

你可以尝试这样的事情：

var ele = document.querySelectorAll('[role="presentation"]');
ele[0].classList.remove("active"); //Remove active class for first element
ele[ele.length- 1].classList.add("active"); //Apply active class for last element
console.log(ele)

Answer 3

var eleLi = document.querySelectorAll('[role="presentation"]');  
for (var i = 0; i < eleLi.length; i++) {
    //remove class active
    eleLi[i].classList.remove('active');
}

//x is an index of li that you want to add the class. Such as 0,1,2
var x = eleLi.length - 1;

//add class active
eleLi[x].classList.add('active');