刷新页面后将类保存到图标

Question

我有这个代码：   <div class="places-item">      <div class="places-item-img"></div>      <div class="places-item-header">         <h2>Machu Picchu, Peru</h2>         <div class="places-item-header-add"><svg xmlns='http://www.w3.org/2000/svg' width='512' height='512' viewBox='0 0 512 512'><path d='M352,48H160a48,48,0,0,0-48,48V464L256,336,400,464V96A48,48,0,0,0,352,48Z' style='fill:transparent;stroke:#000;stroke-linecap:round;stroke-linejoin:round;stroke-width:32px'/></svg></div>      </div>   </div>   <div class="places-item">      <div class="places-item-img"></div>      <div class="places-item-header">         <h2>Ciucaș Peak, Romania</h2>         <div class="places-item-header-add"><svg xmlns='http://www.w3.org/2000/svg' width='512' height='512' viewBox='0 0 512 512'><path d='M352,48H160a48,48,0,0,0-48,48V464L256,336,400,464V96A48,48,0,0,0,352,48Z' style='fill:transparent;stroke:#000;stroke-linecap:round;stroke-linejoin:round;stroke-width:32px'/></svg></div>      </div>   </div>.places-item {    width: 100%;}.places-item-img {    width: 100%;    height: 350px;  background-color: cyan;}.places-item-header {    display: flex;    justify-content: space-between;    align-items: center;    padding: 1em 0;}.places-item-header h2 {    font-size: 24px;    max-width: calc(100% - 38px);}.places-item-header-add {    width: 28px;    height: 28px;    cursor: pointer;}.places-item-header-add svg {    width: 100%;    height: 100%;}.places-item-header-add.added svg path {    fill: #000 !important;}var addBtn = document.querySelectorAll('.places-item-header-add');for(i=0;i<addBtn.length;++i)addBtn[i].addEventListener('click',function(){  this.classList.toggle('added');});当你点击该图标时，它会变成黑色。如何使刷新页面后被点击的图标（可能有多个）变成黑色？我打算在 localStorage 中执行此操作。

Answer 1

针对您的元素，添加 id，以便我们可以指定哪个项目处于活动状态。例子。

将 id 添加到您的项目标题中。 <div id='peru' class="places-item-header-add">

当窗口加载时，检查本地存储中的值并更新项目类。

var addBtn = document.querySelectorAll('.places-item-header-add');

var items = JSON.parse(localStorage.getItem('selected_items')) || {};

for (i = 0; i < addBtn.length; ++i) {

  if (items[addBtn[i].id]) {

    addBtn[i].classList.add('added');

  }

  addBtn[i].addEventListener('click', function() {

    this.classList.toggle('added');

    if (this.classList.contains('added')) {

      items[this.id] = true;

    } else {

      items[this.id] = false;

    }

    localStorage.setItem('selected_items', JSON.stringify(items));

  })

}

检查这个小提琴 https://jsfiddle.net/uwqevc65/