前端drag api课程表demo

HTML

  <div>
    <h1 style="text-align: center">课程表h1>
    <div class="container">
      <div class="left" data-drop="move">
        
        <div data-effect="copy" draggable="true" class="color1 item">语文div>
        <div data-effect="copy" draggable="true" class="color2 item">数学div>
        <div data-effect="copy" draggable="true" class="color3 item">英语div>
        <div data-effect="copy" draggable="true" class="color4 item">政治div>
        <div data-effect="copy" draggable="true" class="color5 item">历史div>
        <div data-effect="copy" draggable="true" class="color6 item">地理div>
        <div data-effect="copy" draggable="true" class="color7 item">物理div>
      div>
      <div class="right">
        <table>
          <tr>
            <th>周一th>
            <th>周二th>
            <th>周三th>
            <th>周四th>
            <th>周五th>
            <th>周六th>
            <th>周日th>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
          <tr>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
            <td data-drop="copy">td>
          tr>
        table>
      div>
    div>
  div>

CSS

    .color1 {
      background-color: pink;
    }

    .color2 {
      background-color: greenyellow;
    }

    .color3 {
      background-color: burlywood;
    }

    .color4 {
      background-color: orangered;
    }

    .color5 {
      background-color: orange;
    }

    .color6 {
      background-color: purple;
    }

    .color7 {
      background-color: peru;
    }

    .container {
      display: flex;
      margin: 50px;
    }

    .left {
      background-color: rgba(223, 223, 216, 0.867);
      padding: 30px 5px;
    }

    .item {
      width: 60px;
      height: 40px;
      text-align: center;
      line-height: 40px;
      border: 1px solid #000;
      margin: 5px 0;
    }

    .right {
      margin-left: 50px;
      box-sizing: border-box;
      background-color: rgba(192, 192, 186, 0.867);
    }

    table {
      border: 1px solid black;
    }

    th {
      width: 60px;
      height: 40px;
      padding: 10px;
      margin: 2px;
      line-height: 40px;
      border-radius: 2px;
    }

    td {
      width: 60px;
      height: 40px;
      padding: 10px;
      margin: 2px;
      border-radius: 2px;
      background-color: #fff;
    }

    .drop-over {
      background-color: rgba(192, 192, 186, 0.867);
    }

JS

// 父级事件委托
const container = document.querySelector('.container')

// // 开始拖拽(只触发一次)
// // e.target拖拽元素
// container.ondragstart = (e) => {
//   console.log('start', e.target)
// }

// // 拖拽到了哪个元素上(频繁触发-350ms)
// // e.target拖拽到了哪个元素之上
// container.ondragover = (e) => {
//   // console.log('over', e.target)
// }

// // 拖拽到了哪个元素上(拖拽到对应元素只触发一次)
// // e.target拖拽到了哪个元素之上
// container.ondragenter = (e) => {
//   console.log('enter', e.target)
// }

// // 松开鼠标时拖拽到哪个元素上
// // e.target拖拽到了哪个元素之上
// container.ondrop = (e) => {
//   console.log('drop', e.target)
// }
// // 直接使用无法触发该事件 因为浏览器默认行为不支持拖拽到元素上
// // 因此要阻止默认行为
// container.ondragover = (e) => {
//   e.preventDefault()
// }

let source
// 功能实现
container.ondragstart = (e) => {
  // 设置拖拽时鼠标状态，取自定义属性
  e.dataTransfer.effectAllowed = e.target.dataset.effect

  source = e.target
}

container.ondragover = (e) => {
  e.preventDefault()
}

function clearDropStyle() {
  document.querySelectorAll('.drop-over').forEach((node) => {
    node.classList.remove('drop-over')
  })
}

// 之前的代码在实现的时候，只考虑了该元素拖拽到空白元素的场景
// 但是拖拽到同级元素，也要找到父元素进行替换，直到找到存在drop
function getDropNode(node) {
  while (node && !node.dataset?.drop) {
    node = node.parentNode
  }
  return node
}

container.ondragenter = (e) => {
  // 清除之前的样式
  clearDropStyle()
  const dropNode = getDropNode(e.target)
  // 当目标元素的自定义属性drop等于目前拖动元素属性时，代表该节点接受拖拽
  if (dropNode && dropNode.dataset.drop === e.dataTransfer.effectAllowed) {
    // 当拖拽元素移入时，添加阴影
    dropNode.classList.add('drop-over')
  }
}

container.ondrop = (e) => {
  clearDropStyle()
  const dropNode = getDropNode(e.target)
  if (dropNode && dropNode.dataset.drop === e.dataTransfer.effectAllowed) {
    if (dropNode.dataset.drop === 'copy') {
      dropNode.innerHTML = ''
      const cloned = source.cloneNode(true)
      // 复制过后的节点改为move属性
      cloned.dataset.effect = 'move'
      dropNode.appendChild(cloned)
    } else {
      // 拖回去删除该节点
      source.remove()
    }
  }
}