HTML ondragenter Attribute

HTML ondragenter Attribute fires when a draggable element enters a valid drop target. And the ondragenter and ondragleave events can help the user to understand that a draggable element is about to enter or leave a drop target. This can be done by, for example, setting a background color when the draggable element enters the drop target and removing the color when the element is moved out of the target.

HTML ondragenter Attribute

The HTML ondragenter attribute can be applied on all the HTML elements.

There are many event attributes that are used and can occur, in the different stages of a drag and drop operation.

Events fired on the draggable target (the source element)

ondragstart – fires when the user starts to drag an element
ondrag – fires when an element is being dragged
ondragend – fires when the user has finished dragging the element

Events fired on the drop target

ondragenter – fires when the dragged element enters the drop target
ondragover – fires when the dragged element is over the drop target
ondragleave – fires when the dragged element leaves the drop target
ondrop – fires when the dragged element is dropped on the drop target

Browser Support

This attribute is supported by the following browsers:

Chrome-4.0
Internet Explorer-9.0
Safari-6.0
Opera-12.0
Firefox-3.5

Example: for <div> element

<!DOCTYPE HTML>
<html>
<head>
<style>
.droptarget {
  float: left; 
  width: 100px; 
  height: 35px;
  margin: 15px;
  margin-right: 100px;
  padding: 10px;
  border: 1px solid #aaaaaa;
}
</style>
</head>
<body>

<p>Drag the p element back and forth between the two rectangles:</p>

<div class="droptarget" ondrop="drop(event)" ondragenter="dragEnter(event)" ondragleave="dragLeave(event)" ondragover="allowDrop(event)">
  <p ondragstart="dragStart(event)" draggable="true" id="dragtarget">Drag me!</p>
</div>

<div class="droptarget" ondragenter="dragEnter(event)" ondragleave="dragLeave(event)" ondrop="drop(event)" ondragover="allowDrop(event)"></div>

<p style="clear:both;"></p>

<p id="demo"></p>

<script>
function dragStart(event) {
  event.dataTransfer.setData("Text", event.target.id);
}

function dragEnter(event) {
  if ( event.target.className == "droptarget" ) {
    event.target.style.border = "3px dotted red";
    document.getElementById("demo").innerHTML = "Entered the dropzone";
  }
}

function dragLeave(event) {
  if ( event.target.className == "droptarget" ) {
    event.target.style.border = "";
    document.getElementById("demo").innerHTML = "Left the dropzone";
  }
}

function allowDrop(event) {
  event.preventDefault();
}

function drop(event) {
  event.preventDefault();
  var data = event.dataTransfer.getData("Text");
  event.target.appendChild(document.getElementById(data));
}
</script>

</body>
</html>

Output:

HTML ondragneter attribute