---
id: html-drag-and-drop
title: "HTML Drag and Drop"
category: "Frontend"
status: "draft"
verification_status: "conceptual"
canonical_id: ""
aliases: ["Drag and Drop API", "draggable attribute", "dataTransfer", "ondragstart", "ondrop", "HTML5 drag and drop"]
duplicate_of: ""
source_trust_level: "B"
confidence_score: 0.89
created_at: 2026-06-23
updated_at: 2026-06-23
review_reason: ""
merge_history: []
tags: ["html", "web", "frontend", "w3schools", "drag-and-drop", "api", "html5"]
raw_sources: ["https://www.w3schools.com/html/html5_draganddrop.asp"]
applied_in: []
github_commit: ""
---

# [[HTML Drag and Drop]]

## 🎯 한 줄 통찰 (One-line insight)
The HTML Drag and Drop API lets an element be dragged and dropped by marking it `draggable="true"` and wiring `ondragstart`, `ondragover`, and `ondrop` handlers that pass data through the `dataTransfer` object. [S1]

## 🧠 핵심 개념 (Core concepts)
- **Drag and Drop API** — enables an element to be dragged and dropped, a common interaction where users grab an object and move it elsewhere. [S1]
- **`draggable="true"`** — the attribute that makes an element draggable. [S1]
- **`dataTransfer`** — the object that carries data between the drag source and drop target via `setData()` / `getData()`. [S1]
- **Default targets reject drops** — elements cannot receive drops by default; you must call `preventDefault()` in the dragover handler to allow a drop. [S1]

## 🧩 추출된 패턴 (Extracted patterns)
- **`ondragstart` + `setData()`** — when dragging starts, store the data type and the dragged element's value. [S1]
- **`ondragover` + `preventDefault()`** — allow dropping by preventing the default behavior that blocks it. [S1]
- **`ondrop` + `getData()` + `appendChild()`** — on drop, retrieve the data using the same type used in `setData()`, then move the element into the drop target. [S1]

## 📖 세부 내용 (Details)
**What it is**
The HTML Drag and Drop API enables an element to be dragged and dropped. Browser support begins with Chrome 4.0, Internet Explorer 9.0, Firefox 3.5, Safari 6.0, and Opera 12.0. [S1]

**Make an element draggable**
Set the `draggable` attribute to `true`: [S1]
```html
<img id="img1" draggable="true">
```
or
```html
<p id="p1" draggable="true">Draggable text</p>
```

**Complete example**
```html
<!DOCTYPE HTML>
<html>
<head>
<script>
function dragstartHandler(ev) {
  ev.dataTransfer.setData("text", ev.target.id);
}

function dragoverHandler(ev) {
  ev.preventDefault();
}

function dropHandler(ev) {
  ev.preventDefault();
  const data = ev.dataTransfer.getData("text");
  ev.target.appendChild(document.getElementById(data));
}
</script>
</head>
<body>

<div id="div1" ondrop="dropHandler(event)" ondragover="dragoverHandler(event)"></div>

<img id="img1" src="img_logo.gif" draggable="true" ondragstart="dragstartHandler(event)" width="336" height="69">

</body>
</html>
```

**The events explained**
- **`ondragstart` and `setData()`** — the `dataTransfer.setData()` method sets the data type and the value of the dragged data. [S1]
- **`ondragover`** — by default, elements cannot receive drops. To allow a drop, call `preventDefault()` in the dragover handler. [S1]
- **`ondrop`** — when the dragged data is dropped, retrieve it via `dataTransfer.getData()` using the same type that was specified in `setData()`. The example then appends the dragged element into the drop target. [S1]

## 🛠️ 적용 사례 (Applied in summary)
The complete example above is the canonical applied case: dragging an `<img>` into a `<div>` drop zone. No external project/commit applications found in the source.

## 💻 코드 패턴 (Code patterns)
Drag start — store the id (JavaScript):
```javascript
function dragstartHandler(ev) {
  ev.dataTransfer.setData("text", ev.target.id);
}
```
Allow drop (JavaScript):
```javascript
function dragoverHandler(ev) {
  ev.preventDefault();
}
```
Perform drop — move the element (JavaScript):
```javascript
function dropHandler(ev) {
  ev.preventDefault();
  const data = ev.dataTransfer.getData("text");
  ev.target.appendChild(document.getElementById(data));
}
```

## ⚖️ 모순 및 업데이트 (Contradictions & updates)
No contradictions found in the source. Note the non-obvious requirement: a drop target rejects drops unless `preventDefault()` is called in its dragover handler. [S1]

## ✅ 검증 상태 및 신뢰도
- **상태:** draft
- **검증 단계:** conceptual (실제 적용 사례 발견 시 applied/validated로 승격 가능)
- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
- **신뢰 점수:** 0.89
- **중복 검사 결과:** 신규 생성 (New discovery)

## 🔗 지식 그래프 (Knowledge Graph)
- **상위/루트:** [[HTML Tutorial]]
- **관련 개념:** [[HTML Web APIs]], [[HTML Geolocation]], [[HTML Web Storage]], [[HTML Web Workers]]
- **참조 맥락:** Referenced whenever building interactive UIs where users rearrange or move elements directly.

## 📚 출처 (Sources)
- [S1] W3Schools — HTML Drag and Drop — https://www.w3schools.com/html/html5_draganddrop.asp

## 📝 변경 이력 (Change history)
- 2026-06-23: Initial draft synthesized from the W3Schools "HTML Drag and Drop" page (Astra wiki-curation, P-Reinforce v3.1 format).
