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DataTransferItemList: clear() method

files/en-us/web/api/datatransferitemlist/clear/index.md

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{{APIRef("HTML Drag and Drop API")}}

The {{domxref("DataTransferItemList")}} method clear() removes all {{domxref("DataTransferItem")}} objects from the drag data items list, leaving the list empty.

The drag data store in which this list is kept is only writable while handling the {{domxref("HTMLElement/dragstart_event", "dragstart")}} event. While handling {{domxref("HTMLElement/drop_event", "drop")}}, the drag data store is in read-only mode, and this method silently does nothing. No exception is thrown.

Syntax

js-nolint
clear()

Parameters

None.

Return value

None ({{jsxref("undefined")}}).

Examples

This example shows the use of the clear() method.

HTML

html
<div>
  <p id="source" 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">Drop Zone</div>

CSS

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

JavaScript

js
const source = document.getElementById("source");
const target = document.getElementById("target");

source.addEventListener("dragstart", (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");
});

source.addEventListener("dragend", (ev) => {
  console.log("dragEnd");
  const dataList = ev.dataTransfer.items;

  // Clear any remaining drag data
  dataList.clear();
});

target.addEventListener("drop", (ev) => {
  console.log("Drop");
  ev.preventDefault();

  // Loop through the dropped items and log their data
  for (const item of ev.dataTransfer.items) {
    if (item.kind === "string" && item.type.match(/^text\/plain/)) {
      // This item is the target node
      item.getAsString((s) => {
        ev.target.appendChild(document.getElementById(s));
      });
    } else if (item.kind === "string" && item.type.match(/^text\/html/)) {
      // Drag data item is HTML
      item.getAsString((s) => {
        console.log(`… Drop: HTML = ${s}`);
      });
    } else if (item.kind === "string" && item.type.match(/^text\/uri-list/)) {
      // Drag data item is URI
      item.getAsString((s) => {
        console.log(`… Drop: URI = ${s}`);
      });
    }
  }
});

target.addEventListener("dragover", (ev) => {
  console.log("dragOver");
  ev.preventDefault();

  // Set the dropEffect to move
  ev.dataTransfer.dropEffect = "move";
});

Result

{{EmbedLiveSample('Examples', 400, 300)}}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}