HTMLElement: drag 事件
當用戶正在拖動一個元素或文字選擇時，每隔幾百毫秒就會觸發一次 drag 事件。
語法
在諸如 addEventListener() 之類的方法中使用事件名稱，或設定事件處理程式屬性。
js
addEventListener("drag", (event) => { })
ondrag = (event) => { }
事件型別
事件屬性
除了下面列出的屬性之外，父介面 Event 的屬性也可使用。
DragEvent.dataTransfer只讀-
在拖放互動期間傳輸的資料。
示例
拖放示例
HTML
html
<div class="dropzone">
<div id="draggable" draggable="true">This div is draggable</div>
</div>
<div class="dropzone" id="drop-target"></div>
CSS
css
body {
/* Prevent the user selecting text in the example */
user-select: none;
}
#draggable {
text-align: center;
background: white;
}
.dropzone {
width: 200px;
height: 20px;
background: blueviolet;
margin: 10px;
padding: 10px;
}
.dropzone.dragover {
background-color: purple;
}
.dragging {
opacity: 0.5;
}
JavaScript
js
let dragged;
/* events fired on the draggable target */
const source = document.getElementById("draggable");
source.addEventListener("drag", (event) => {
console.log("dragging");
});
source.addEventListener("dragstart", (event) => {
// store a ref. on the dragged elem
dragged = event.target;
// make it half transparent
event.target.classList.add("dragging");
});
source.addEventListener("dragend", (event) => {
// reset the transparency
event.target.classList.remove("dragging");
});
/* events fired on the drop targets */
const target = document.getElementById("drop-target");
target.addEventListener("dragover", (event) => {
// prevent default to allow drop
event.preventDefault();
});
target.addEventListener("dragenter", (event) => {
// highlight potential drop target when the draggable element enters it
if (event.target.classList.contains("dropzone")) {
event.target.classList.add("dragover");
}
});
target.addEventListener("dragleave", (event) => {
// reset background of potential drop target when the draggable element leaves it
if (event.target.classList.contains("dropzone")) {
event.target.classList.remove("dragover");
}
});
target.addEventListener("drop", (event) => {
// prevent default action (open as link for some elements)
event.preventDefault();
// move dragged element to the selected drop target
if (event.target.classList.contains("dropzone")) {
event.target.classList.remove("dragover");
event.target.appendChild(dragged);
}
});
結果
規範
| 規範 |
|---|
| HTML # handler-ondrag |
| HTML # event-dnd-drag |
瀏覽器相容性
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