HTMLElement：drag 事件

drag 事件在用户拖动元素或选择的文本时，每隔几百毫秒就会被触发一次。

语法

在类似 addEventListener() 这样的方法中使用事件名称，或设置事件处理器属性。

addEventListener('drag', (event) => {});

ondrag = (event) => { };

事件类型

一个 DragEvent。继承自 Event。

Event UIEvent MouseEvent DragEvent

事件属性

除了下面列出的属性外，还可以使用父接口 Event 的属性。

DragEvent.dataTransfer 只读

在进行拖放操作时，传输的数据。

示例

拖放示例

HTML

<div class="dropzone">
  <div id="draggable" draggable="true">
    这个 div 可以拖动
  </div>
</div>
<div class="dropzone" id="droptarget"></div>

CSS

body {
  /* Prevent the user selecting text in the example */
  user-select: none;
}

#draggable {
  text-align: center;
  background: white;
}

.dropzone {
  width: 200px;
  height: 20px;
  background: blueviolet;
  margin: 10px;
  padding: 10px;
}

.dropzone.dragover {
  background-color: purple;
}

.dragging {
  opacity: .5;
}

JavaScript

let dragged;

/* events fired on the draggable target */
const source = document.getElementById("draggable");
source.addEventListener("drag", (event) => {
  console.log("dragging");
});

source.addEventListener("dragstart", (event) => {
  // store a ref. on the dragged elem
  dragged = event.target;
  // make it half transparent
  event.target.classList.add("dragging");
});

source.addEventListener("dragend", (event) => {
  // reset the transparency
  event.target.classList.remove("dragging");
});

/* events fired on the drop targets */
const target = document.getElementById("droptarget");
target.addEventListener("dragover", (event) => {
  // prevent default to allow drop
  event.preventDefault();
}, false);

target.addEventListener("dragenter", (event) => {
  // highlight potential drop target when the draggable element enters it
  if (event.target.classList.contains("dropzone")) {
    event.target.classList.add("dragover");
  }
});

target.addEventListener("dragleave", (event) => {
  // reset background of potential drop target when the draggable element leaves it
  if (event.target.classList.contains("dropzone")) {
    event.target.classList.remove("dragover");
  }
});

target.addEventListener("drop", (event) => {
  // prevent default action (open as link for some elements)
  event.preventDefault();
  // move dragged element to the selected drop target
  if (event.target.classList.contains("dropzone")) {
    event.target.classList.remove("dragover");
    dragged.parentNode.removeChild(dragged);
    event.target.appendChild(dragged);
  }
});

结果

规范

Specification
HTML Standard
# ix-handler-ondrag
HTML Standard
# event-dnd-drag

浏览器兼容性

BCD tables only load in the browser

参见