DataTransferItemList.length

The read-only length property of the DataTransferItemList interface returns the number of items currently in the drag item list.

Syntax

length = DataTransferItemList.length;

Value

The number of drag data items in the list, or 0 if the list is empty or disabled. The drag item list is considered to be disabled if the item list's DataTransfer object is not associated with a drag data store.

Example

This example shows the use of the length property.

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

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;
}

Result

Drag and Drop demo link

Specifications

Specification Status Comment
HTML Living Standard
The definition of 'length' in that specification.
Living Standard  
HTML 5.1
The definition of 'length' in that specification.
Recommendation Not included in W3C HTML5 Recommendation

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support 4Edge Full support YesFirefox Full support 50IE No support NoOpera Full support 12Safari No support NoWebView Android No support NoChrome Android No support NoEdge Mobile Full support YesFirefox Android Full support 50Opera Android No support NoSafari iOS No support NoSamsung Internet Android ?

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown

Document Tags and Contributors

Contributors to this page: mfuji09, fscholz, Sheppy, nvlled, enishina, erikadoyle, rolfedh, AFBarstow
Last updated by: mfuji09,