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Execute a JavaScript when an element is being dragged over a drop target
The ondragover event occurs when a draggable element or text selection is being dragged over a valid drop target.
By default, data/elements cannot be dropped in other elements. To allow a drop, we must prevent the default handling of the element. This is done by calling the event.preventDefault() method for the ondragover event.
Drag and drop is a very common feature in HTML5. It is when you "grab" an object and drag it to a different location. For more information, see our HTML Tutorial on HTML5 Drag and Drop.
There are many events that are used, and can occur, in the different stages of a drag and drop operation:
The numbers in the table specify the first browser version that fully supports the event.
| Event | |||||
|---|---|---|---|---|---|
| ondragover | 4.0 | 9.0 | 3.5 | 6.0 | 12.0 |
In HTML:
<element ondragover="myScript">
In JavaScript:
object.ondragover = function(){myScript};
In JavaScript, using the addEventListener() method:
object.addEventListener("dragover", myScript);
| Bubbles: | Yes |
|---|---|
| Cancelable: | Yes |
| Event type: | DragEvent |
| Supported HTML tags: | All HTML elements |
| DOM Version: | Level 3 Events |
A demonstration of ALL possible drag and drop events:
<p draggable="true" id="dragtarget">Drag me!</p>
<div class="droptarget">Drop here!</div>
<script>
// Events fired on the drag target
document.addEventListener("dragstart", function(event) {
// The dataTransfer.setData() method sets the data type and the value of the dragged data
event.dataTransfer.setData("Text", event.target.id);
// Output some text when starting to drag the p element
document.getElementById("demo").innerHTML = "Started to drag the p element.";
// Change the opacity of the draggable element
event.target.style.opacity = "0.4";
});
// While dragging the p element, change the color of the output text
document.addEventListener("drag", function(event) {
document.getElementById("demo").style.color = "red";
});
// Output some text when finished dragging the p element and reset the opacity
document.addEventListener("dragend", function(event) {
document.getElementById("demo").innerHTML = "Finished dragging the p element.";
event.target.style.opacity = "1";
});
// Events fired on the drop target
// When the draggable p element enters the droptarget, change the DIVS's border style
document.addEventListener("dragenter", function(event) {
if ( event.target.className == "droptarget" ) {
event.target.style.border = "3px dotted red";
}
});
// By default, data/elements cannot be dropped in other elements. To allow a drop, we must prevent the default handling of the element
document.addEventListener("dragover", function(event) {
event.preventDefault();
});
// When the draggable p element leaves the droptarget, reset the DIVS's border style
document.addEventListener("dragleave", function(event) {
if ( event.target.className == "droptarget" ) {
event.target.style.border = "";
}
});
/* On drop - Prevent the browser default handling of the data (default is open as link on drop)
Reset the color of the output text and DIV's border color
Get the dragged data with the dataTransfer.getData() method
The dragged data is the id of the dragged element ("drag1")
Append the dragged element into the drop element
*/
document.addEventListener("drop", function(event) {
event.preventDefault();
if ( event.target.className == "droptarget" ) {
document.getElementById("demo").style.color = "";
event.target.style.border = "";
var data = event.dataTransfer.getData("Text");
event.target.appendChild(document.getElementById(data));
}
});
</script>
HTML Tutorial: HTML5 Drag and Drop
HTML Reference: HTML draggable Attribute