DataTransfer: setData() method
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The setData() method of the DataTransfer interface 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 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 types list is not changed when replacing data of the same type.
Example data types are text/plain and text/uri-list.
During a drag operation, this method can only be used in the handler for the dragstart event, because that's the only time the drag operation's data store is writable. Calling it from any other drag event does nothing. See Modifying the drag data store for details.
Syntax
setData(format, data)
Parameters
format-
A string representing the type of the drag data to add to the
DataTransfer. data-
A string representing the data to add to the
DataTransfer.
Return value
None (undefined).
Examples
Dragging an element
In this example we can drag a <p> element into a target <div> element.
-
In the
dragstarthandler, we usesetData()to add theidof the<p>element to theDataTransferobject. -
In the
drophandler we retrieve theidand 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
Specifications
| Specification |
|---|
| HTML # dom-datatransfer-setdata-dev |