References

Beginner-friendly references for web development, with live, editable examples.

The HTML ondragenter event

Event All modern browsers Updated
Quick answer

The HTML ondragenter attribute runs JavaScript when a dragged item enters a valid drop target. It is an inline handler for the dragenter event; in modern code prefer addEventListener('dragenter', …).

Overview

The ondragenter event attribute runs JavaScript when a dragged item enters a drop target. In JavaScript the event itself is named dragenter — drop the on prefix when you call addEventListener.

It is part of the native HTML drag-and-drop API. The handler receives a DragEvent whose dataTransfer object carries the dragged data. One rule trips everyone up: you must call event.preventDefault() in the ondragover handler of a target, or it will not accept a drop.

You can wire this up with the inline ondragenter HTML attribute, but the modern, recommended approach is element.addEventListener('dragenter', handler) in JavaScript. That keeps behavior out of your markup, lets you attach several handlers to the same event, and makes them easy to remove. The inline attribute is fine for quick demos.

Syntax

<element ondragenter="handler()">…</element>

element.addEventListener('dragenter', handler);

Best practices

  • Prefer element.addEventListener('dragenter', handler) over the inline ondragenter attribute — it separates behavior from markup and allows multiple handlers.
  • Call preventDefault() in ondragover so the element can act as a drop target.
  • Set and read the payload through event.dataTransfer.
  • Provide a keyboard-accessible alternative — native drag-and-drop is hard to use without a mouse.

Frequently asked questions

What is the ondragenter event?
It runs JavaScript when a dragged item enters a drop target. In JavaScript the event is named dragenter.
Why is my drop not working?
You must call event.preventDefault() in the ondragover handler, otherwise the element rejects the drop.
How do I pass data between dragged and dropped elements?
Use event.dataTransfer.setData() when the drag starts and getData() when it drops.
Should I use the ondragenter attribute or addEventListener?
Prefer addEventListener('dragenter', …) in JavaScript. The inline ondragenter attribute works but mixes behavior into the markup and allows only one handler per element.
ondragend ondragleave