DataTransfer: setData() method

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

The DataTransfer.setData() method sets the drag operation’s drag data to the specified data and type. If data for the given type does not exist, it is added at the end of the drag data store, such that the last item in the {{domxref("DataTransfer.types","types")}} list will be the new type. If data for the given type already exists, the existing data is replaced in the same position. That is, the order of the {{domxref("DataTransfer.types","types")}} list is not changed when replacing data of the same type.

Example data types are text/plain and text/uri-list.

Syntax

setData(format, data)

Parameters

format
- : A string representing the type of the drag data to add to the {{domxref("DataTransfer")}} .
data
- : A string representing the data to add to the {{domxref("DataTransfer")}} .

Return value

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

Examples

Dragging an element

In this example we can drag a {{HTMLElement("p")}} element into a target {{HTMLElement("div")}} element.

In the dragstart handler, we use setData() to add the id of the <p> element to the {{domxref("DataTransfer")}} object.
In the drop handler we retrieve the id and use it to move the <p> element into the target.

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>

<button id="reset">Reset example</button>

CSS

div {
  margin: 0.5em 0;
  padding: 2em;
}

#target,
#source {
  border: 1px solid black;
  padding: 0.5rem;
}

.dragging {
  background-color: pink;
}

JavaScript

const source = document.querySelector("#source");
source.addEventListener("dragstart", (ev) => {
  console.log("dragStart");
  // Change the source element's background color
  // to show that drag has started
  ev.currentTarget.classList.add("dragging");
  // Clear the drag data cache (for all formats/types)
  ev.dataTransfer.clearData();
  // Set the drag's format and data.
  // Use the event target's id for the data
  ev.dataTransfer.setData("text/plain", ev.target.id);
});
source.addEventListener("dragend", (ev) =>
  ev.target.classList.remove("dragging"),
);

const target = document.querySelector("#target");
target.addEventListener("dragover", (ev) => {
  console.log("dragOver");
  ev.preventDefault();
});
target.addEventListener("drop", (ev) => {
  console.log("Drop");
  ev.preventDefault();
  // Get the data, which is the id of the source element
  const data = ev.dataTransfer.getData("text");
  const source = document.getElementById(data);
  ev.target.appendChild(source);
});

const reset = document.querySelector("#reset");
reset.addEventListener("click", () => document.location.reload());

Result

{{EmbedLiveSample("Dragging an element", "", 250)}}

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

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