刷新页面后将类保存到图标中

Question

我有此代码：

   <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');
});

当您单击图标时，它变为黑色。刷新页面后，如何使被单击的图标（可能有几个）变黑？我打算在localStorage上执行此操作。

Answer 1

特定于您的元素，添加ID，以便我们可以指定哪个项目处于活动状态。例如。

在您的项目标题中添加ID。<div id='peru' class="places-item-header-add">

并且在加载窗口时检查localstorage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));
  })
}

检查此小提琴https://jsfiddle.net/uwqevc65/