HTMLElement:drag 事件
drag
事件在用户拖动元素或选择的文本时,每隔几百毫秒就会被触发一次。
语法
在类似 addEventListener()
这样的方法中使用事件名称,或设置事件处理器属性。
addEventListener('drag', (event) => {});
ondrag = (event) => { };
事件类型
事件属性
除了下面列出的属性外,还可以使用父接口 Event
的属性。
DragEvent.dataTransfer
只读-
在进行拖放操作时,传输的数据。
示例
拖放示例
HTML
<div class="dropzone">
<div id="draggable" draggable="true">
这个 div 可以拖动
</div>
</div>
<div class="dropzone" id="droptarget"></div>
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: .5;
}
JavaScript
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("droptarget");
target.addEventListener("dragover", (event) => {
// prevent default to allow drop
event.preventDefault();
}, false);
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");
dragged.parentNode.removeChild(dragged);
event.target.appendChild(dragged);
}
});
结果
规范
Specification |
---|
HTML Standard # ix-handler-ondrag |
HTML Standard # event-dnd-drag |
浏览器兼容性
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