DataTransferItemList: add() method
==================================

 The **`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` or a string of a
 given type. If the item is successfully added to the list, the newly-created
 `DataTransferItem` object is returned.

Syntax
------


```js
add(data, type)
add(file)
```

### Parameters

`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`

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

### Return value

 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` is returned.

### Exceptions

`NotSupportedError` `DOMException`

 Thrown if the 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.


Examples
--------

This example shows the use of the `add()` method.

### HTML


```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


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

### JavaScript


```js
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
  const 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();
  const data = event.dataTransfer.items;
  // Loop through the dropped items and log their data
  for (let 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((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((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((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");
  const dataList = ev.dataTransfer.items;
  for (let i = 0; i < dataList.length; i++) {
    dataList.remove(i);
  }
  // Clear any remaining drag data
  dataList.clear();
}
```

### Result

Result linkSpecifications
--------------

| Specification |
| --- |
| HTML Standard # dom-datatransferitemlist-add-dev |

Browser compatibility
---------------------

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