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• 句法
• 范例
• 规范
• 浏览器兼容性
• 相关话题

DataTransferItemList.add() method creates a new DataTransferItem using the specified data and adds it to the drag data list. The item may be a File 或 string of a given type. If the item is successfully added to the list, the newly-created DataTransferItem 对象被返回。

句法

DataTransferItem = DataTransferItemList.add(data, type);
DataTransferItem = DataTransferItemList.add(file);
					

参数

data

A string representing the drag item's data.

type

A string of the drag item's type. Some example types are text/html and text/plain .

file

File object. No type needs to be given in this case.

返回值

A DataTransferItem containing the specified data. If the drag item couldn't be created (for example, if the associated DataTransfer object has no data store), null 被返回。

异常

NotSupportedError

A string data parameter was provided, and the list already contains an item whose kind is "Plain Unicode string" and whose type is equal to the specified type parameter.

范例

This example shows the use of the add() 方法。

HTML

<div>
 <p id="source" ondragstart="dragstart_handler(event);" ondragend="dragend_handler(event);" draggable="true">
 Select this element, drag it to the Drop Zone and then release the selection to move the element.</p>
</div>
<div id="target" ondrop="drop_handler(event);" ondragover="dragover_handler(event);">Drop Zone</div>
							

CSS

div {
  margin: 0em;
  padding: 2em;
}
#source {
  color: blue;
  border: 1px solid black;
}
#target {
  border: 1px solid black;
}
							

Javascript

function dragstart_handler(ev) {
  console.log("dragStart");
  // Add this element's id to the drag payload so the drop handler will
  // know which element to add to its tree
  var dataList = ev.dataTransfer.items;
  dataList.add(ev.target.id, "text/plain");
  // Add some other items to the drag payload
  dataList.add("<p>... paragraph ...</p>", "text/html");
  dataList.add("http://www.example.org","text/uri-list");
}
function drop_handler(ev) {
  console.log("Drop");
  ev.preventDefault();
  var data = event.dataTransfer.items;
  // Loop through the dropped items and log their data
  for (var i = 0; i < data.length; i++) {
    if ((data[i].kind == 'string') && (data[i].type.match('^text/plain'))) {
      // This item is the target node
      data[i].getAsString(function (s){
        ev.target.appendChild(document.getElementById(s));
      });
    } else if ((data[i].kind == 'string') && (data[i].type.match('^text/html'))) {
      // Drag data item is HTML
      data[i].getAsString(function (s){
        console.log("... Drop: HTML = " + s);
      });
    } else if ((data[i].kind == 'string') && (data[i].type.match('^text/uri-list'))) {
      // Drag data item is URI
      data[i].getAsString(function (s){
        console.log("... Drop: URI = " + s);
      });
    }
  }
}
function dragover_handler(ev) {
  console.log("dragOver");
  ev.preventDefault();
  // Set the dropEffect to move
  ev.dataTransfer.dropEffect = "move"
}
function dragend_handler(ev) {
  console.log("dragEnd");
  var dataList = ev.dataTransfer.items;
  for (var i = 0; i < dataList.length; i++) {
    dataList.remove(i);
  }
  // Clear any remaining drag data
  dataList.clear();
}
							

结果

Result link

规范

规范	状态	注释
HTML 实时标准 The definition of 'add()' in that specification.	实时标准
HTML 5.1 The definition of 'add()' in that specification.	推荐	Not included in W3C HTML5 推荐

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
add	Chrome 13	Edge 12 — 79	Firefox 50	IE No	Opera 12	Safari 6	WebView Android 4.4	Chrome Android 18	Firefox Android 50	Opera Android No	Safari iOS 6	Samsung Internet Android 1.0

图例

完整支持

完整支持

不支持

不支持

元数据

• 最后修改： 2019 年 3 月 23 日

相关话题

1. HTML 拖放 API
2. DataTransferItemList
3. 特性

   1. length
4. 方法

   1. add()
   2. clear()
   3. DataTransferItem()
   4. remove()
5. Related pages for HTML Drag and Drop API

   1. DataTransfer
   2. DataTransferItem
   3. DragEvent