DataTransferItemList.remove() - Web APIs 编辑

The DataTransferItemList.remove() method removes the DataTransferItem at the specified index from the list. If the index is less than zero or greater than one less than the length of the list, the list will not be changed.

Syntax

DataTransferItemList.remove(index);

Parameters

index

The zero-based index number of the item in the drag data list to remove. If the index doesn't correspond to an existing item in the list, the list is left unchanged.

Return value

undefined.

Exceptions

InvalidStateError

The drag data store is not in read/write mode, so the item can't be removed.

Example

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

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 = event.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;
  for (var i = 0; i < dataList.length; i++) {
    dataList.remove(i);
  }
  // Clear any remaining drag data
  dataList.clear();
}

HTML

<h1>Example uses of <code>DataTransferItemList</code> methods and property</h1>
 <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;
  }

Specifications

Browser compatibility

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