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原生js实现拖拽上传（拖拽时高亮上传区域）

news 2025/9/13 5:03:41

文章目录

drop相关事件说明-MDN
演示
代码（.html)

drop相关事件说明-MDN

演示

在这里插入图片描述

代码（.html)

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Drag Upload</title><style>html,body {height: 100%;width: 100%;}.drag-upload-box {width: 200px;height: 130px;border-radius: 6px;border: 2px dashed #ccc;overflow: hidden;display: flex;align-items: center;justify-content: center;cursor: pointer;}.drag-upload-box.guide {border-color: orange;}.drag-upload-box.available {border-color: green;}.drag-upload-box > * {/* 防止拖拽到 子元素导致触发 dragleave*/pointer-events: none;}.drag-upload-box .empty {color: #ccc;}.drag-upload-box .file-name:empty + .empty {display: unset;}.drag-upload-box .file-name + .empty {display: none;}.input-file {display: none;}.obstacle {width: 100%;height: 200px;background: #ccc;}</style>
</head><body><div id="root"><div id="upload" class="drag-upload-box"><input id="file" class="input-file" type="file"><span class="file-name"></span><span class="tips empty">点击/拖拽到此处上传文件</span></div><div class="obstacle no1">其他元素</div></div></body>
<script>const $ = selector => document.querySelector(selector)const addEvent = (element, event, handler) => element.addEventListener(event, handler)// 文件上传inputconst fileInput = $('#file')// 拖放区域const dragBox = $('#upload')const fileName = dragBox.querySelector('.file-name')const tips = dragBox.querySelector('.tips')// 两个标识；来判断当前鼠标是否在上传文件/body中。let inUploadBox = falselet inBody = false// 绑定拖拽事件addEvent(dragBox, 'dragenter', handlerEvents)addEvent(dragBox, 'dragover', handlerEvents)addEvent(dragBox, 'dragleave', handlerEvents)addEvent(dragBox, 'drop', handlerEvents)// 点击上传addEvent(dragBox, 'click', (e) => {fileInput.click()})// 选择文件回调addEvent(fileInput, 'change', () => {getFile(fileInput.files[0])})const light = {guide() {this.classList.add('guide')this.classList.remove('available')tips.innerText = '拖拽到此处'inUploadBox = false},available() {this.classList.add('available')this.classList.remove('guide')tips.innerText = '松开鼠标'inUploadBox = true},clearLight() {this.removeClass('guide', 'available')tips.innerText = '点击/拖拽到此处上传文件'inUploadBox = false},removeClass() {this.classList.remove(...arguments)return this}}Object.assign(dragBox, light)function handlerEvents(e) {// 阻止事件传播触发 body 的dragovere.stopPropagation()e.preventDefault()// 禁用dragover默认事件，否则会在浏览器中打开文件switch (e.type) {// 进入拖放区域case 'dragenter':dragBox.available()break// 离开拖放区域case 'dragleave':if (inBody) {dragBox.guide()} else {dragBox.clearLight()}break// 在拖拽区域内松开鼠标（拖放完成/放入文件）case 'drop':getFile(e.dataTransfer.files[0])dragBox.clearLight()inBody = falsebreakdefault:break}}// 获取到文件function getFile(file) {console.log(file)if (!file) {fileName.innerText = ''return}const fileSize = (file.size / (1024 * 1024)).toFixed(2) + 'MB'fileName.innerText = file.name + ' ' + fileSize// TODO: 上传、预览}/* 以上是正常拖拽上传部分，下面代码处理拖拽到body后的指引/处理 */const body = document.bodyaddEvent(body, 'dragenter', handlerOutEvents)addEvent(body, 'dragover', handlerOutEvents)addEvent(body, 'dragleave', handlerOutEvents)addEvent(body, 'drop', handlerOutEvents)function handlerOutEvents(e) {e.stopPropagation()e.preventDefault()switch (e.type) {case 'dragenter':// 拖拽到 body && 未到上传文件区域；高亮指引到上传区域dragBox.guide()inBody = truebreakcase 'dragover':breakcase 'dragleave':if (inUploadBox) {dragBox.removeClass('guide')}breakcase 'drop':dragBox.clearLight()inBody = falsebreakdefault:break}}
</script></html>