470 lines
17 KiB
HTML
470 lines
17 KiB
HTML
<!DOCTYPE html>
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<html lang="zh-CN">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>拖拽触发文件下载演示</title>
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<style>
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* {
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margin: 0;
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padding: 0;
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box-sizing: border-box;
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font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
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}
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body {
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background-color: #f5f7fa;
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color: #333;
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line-height: 1.6;
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padding: 20px;
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max-width: 1000px;
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margin: 0 auto;
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}
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header {
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text-align: center;
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margin-bottom: 40px;
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padding-bottom: 20px;
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border-bottom: 1px solid #e1e4e8;
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}
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h1 {
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color: #2c3e50;
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margin-bottom: 10px;
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font-size: 2.5rem;
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}
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.subtitle {
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color: #7f8c8d;
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font-size: 1.1rem;
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}
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.container {
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display: grid;
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grid-template-columns: 1fr 1fr;
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gap: 30px;
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margin-bottom: 40px;
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}
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@media (max-width: 768px) {
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.container {
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grid-template-columns: 1fr;
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}
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}
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.demo-area,
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.explanation {
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background-color: white;
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border-radius: 12px;
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padding: 25px;
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box-shadow: 0 5px 15px rgba(0, 0, 0, 0.08);
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}
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.demo-area h2,
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.explanation h2 {
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color: #3498db;
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margin-bottom: 20px;
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padding-bottom: 10px;
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border-bottom: 2px solid #f0f0f0;
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}
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.draggable-item {
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background: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
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color: white;
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padding: 30px;
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border-radius: 10px;
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text-align: center;
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cursor: grab;
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user-select: none;
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transition: all 0.3s ease;
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margin-bottom: 20px;
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}
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.draggable-item:hover {
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transform: translateY(-5px);
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box-shadow: 0 10px 20px rgba(106, 17, 203, 0.2);
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}
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.draggable-item:active {
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cursor: grabbing;
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transform: translateY(-2px);
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}
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.draggable-icon {
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font-size: 3.5rem;
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margin-bottom: 15px;
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}
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.download-hint {
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background-color: #f8f9fa;
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border-left: 4px solid #3498db;
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padding: 15px;
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margin-top: 20px;
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border-radius: 0 8px 8px 0;
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}
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.file-list {
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margin-top: 20px;
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}
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.file-item {
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display: flex;
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align-items: center;
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padding: 12px 15px;
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margin-bottom: 10px;
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background-color: #f8f9fa;
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border-radius: 8px;
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border: 1px solid #e9ecef;
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}
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.file-icon {
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font-size: 1.5rem;
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margin-right: 12px;
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color: #3498db;
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}
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.file-info {
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flex-grow: 1;
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}
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.file-name {
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font-weight: 600;
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margin-bottom: 3px;
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}
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.file-size {
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font-size: 0.85rem;
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color: #7f8c8d;
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}
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.code-container {
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background-color: #2c3e50;
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color: #ecf0f1;
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padding: 20px;
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border-radius: 8px;
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margin-top: 20px;
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overflow-x: auto;
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font-family: 'Consolas', 'Monaco', monospace;
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font-size: 0.9rem;
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}
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.code-keyword {
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color: #3498db;
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}
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.code-string {
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color: #e74c3c;
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}
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.code-comment {
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color: #7f8c8d;
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}
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.code-function {
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color: #9b59b6;
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}
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.limitations {
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background-color: #fff8e1;
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border: 1px solid #ffd54f;
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padding: 20px;
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border-radius: 8px;
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margin-top: 30px;
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}
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.limitations h3 {
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color: #f39c12;
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margin-bottom: 15px;
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}
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footer {
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text-align: center;
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margin-top: 40px;
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padding-top: 20px;
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border-top: 1px solid #e1e4e8;
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color: #7f8c8d;
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font-size: 0.9rem;
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}
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.status-message {
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margin-top: 20px;
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padding: 12px;
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border-radius: 8px;
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text-align: center;
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font-weight: 600;
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display: none;
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}
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.success {
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background-color: #d4edda;
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color: #155724;
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border: 1px solid #c3e6cb;
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}
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.error {
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background-color: #f8d7da;
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color: #721c24;
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border: 1px solid #f5c6cb;
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}
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.drag-target {
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border: 3px dashed #3498db;
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background-color: rgba(52, 152, 219, 0.05);
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}
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</style>
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</head>
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<body>
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<header>
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<h1>拖拽触发文件下载演示</h1>
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<p class="subtitle">演示如何通过拖拽操作触发浏览器文件下载</p>
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</header>
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<div class="container">
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<div class="demo-area">
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<h2>演示区域</h2>
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<p>将下面的元素拖拽到桌面或文件夹，会触发文件下载到浏览器的默认下载目录。</p>
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<div class="draggable-item" id="draggableElement" draggable="true">
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<div class="draggable-icon">📦</div>
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<h3>拖拽我下载文件</h3>
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<p>按住鼠标左键拖拽到桌面或文件夹</p>
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</div>
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<div class="download-hint">
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<p><strong>提示：</strong> 文件将下载到浏览器的默认下载目录（如"下载"文件夹），而不是直接保存到拖拽的目标位置。</p>
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</div>
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<div class="file-list">
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<p><strong>可下载的文件：</strong></p>
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<div class="file-item">
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<div class="file-icon">📄</div>
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<div class="file-info">
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<div class="file-name">示例文档.txt</div>
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<div class="file-size">文本文件，约 20 字节</div>
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</div>
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</div>
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<div class="file-item">
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<div class="file-icon">🖼️</div>
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<div class="file-info">
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<div class="file-name">demo-image.png</div>
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<div class="file-size">图片文件，约 45 KB</div>
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</div>
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</div>
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<div class="file-item">
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<div class="file-icon">📊</div>
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<div class="file-info">
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<div class="file-name">数据报告.pdf</div>
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<div class="file-size">PDF文档，约 120 KB</div>
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</div>
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</div>
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</div>
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<div id="statusMessage" class="status-message"></div>
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</div>
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<div class="explanation">
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<h2>技术原理</h2>
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<p>这个演示通过以下步骤实现拖拽触发下载：</p>
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<ol>
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<li>为可拖拽元素添加 <code>draggable="true"</code> 属性</li>
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<li>监听 <code>dragstart</code> 事件</li>
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<li>在事件处理函数中，动态创建隐藏的下载链接</li>
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<li>设置链接的 <code>href</code> 和 <code>download</code> 属性</li>
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<li>通过 JavaScript 模拟点击链接，触发下载</li>
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</ol>
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<div class="code-container">
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<pre><code><span class="code-comment">// 获取可拖拽元素</span>
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<span class="code-keyword">const</span> draggable = document.<span class="code-function">getElementById</span>(<span class="code-string">'draggableElement'</span>);
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<span class="code-comment">// 监听拖拽开始事件</span>
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draggable.<span class="code-function">addEventListener</span>(<span class="code-string">'dragstart'</span>, <span class="code-keyword">function</span>(e) {
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<span class="code-comment">// 设置拖拽效果为"复制"</span>
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e.dataTransfer.effectAllowed = <span class="code-string">'copy'</span>;
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<span class="code-comment">// 设置拖拽数据（某些系统需要）</span>
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e.dataTransfer.<span class="code-function">setData</span>(<span class="code-string">'text/plain'</span>, <span class="code-string">'下载文件'</span>);
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<span class="code-comment">// 创建隐藏的下载链接</span>
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<span class="code-keyword">const</span> link = document.<span class="code-function">createElement</span>(<span class="code-string">'a'</span>);
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<span class="code-comment">// 可以根据需要切换不同的文件</span>
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<span class="code-keyword">const</span> fileType = <span class="code-function">getSelectedFileType</span>(); <span class="code-comment">// 假设的函数</span>
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link.href = <span class="code-function">getFileUrl</span>(fileType); <span class="code-comment">// 文件URL</span>
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link.download = <span class="code-function">getFileName</span>(fileType); <span class="code-string">// 下载的文件名</span>
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<span class="code-comment">// 模拟点击触发下载</span>
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document.body.<span class="code-function">appendChild</span>(link);
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link.<span class="code-function">click</span>();
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document.body.<span class="code-function">removeChild</span>(link);
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<span class="code-comment">// 显示状态消息</span>
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<span class="code-function">showStatus</span>(<span class="code-string">'下载已开始，请检查浏览器的下载列表'</span>, <span class="code-string">'success'</span>);
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});</code></pre>
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</div>
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</div>
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</div>
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<div class="limitations">
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<h3>技术限制与注意事项</h3>
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<ul>
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<li>拖拽操作实际上触发的是浏览器的标准下载流程，文件会保存到默认下载目录，而不是拖拽的目标位置</li>
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<li>某些浏览器可能对拖拽触发下载有安全限制</li>
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<li>下载行为受浏览器下载设置的影响（如下载前询问保存位置）</li>
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<li>需要服务器正确设置CORS头部（如果文件来自不同源）</li>
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<li>对于大文件，下载可能在后台进行，用户可能不会立即察觉</li>
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</ul>
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</div>
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<footer>
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<p>演示：拖拽触发文件下载 | 使用 HTML、CSS 和 JavaScript 实现</p>
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<p>注意：这是一个前端技术演示，实际文件下载功能需要配合服务器端或Blob API</p>
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</footer>
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<script>
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document.addEventListener('DOMContentLoaded', function () {
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const draggableElement = document.getElementById('draggableElement');
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const statusMessage = document.getElementById('statusMessage');
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// 模拟可下载的文件数据
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const files = {
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txt: {
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name: "示例文档.txt",
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content: "这是一个通过拖拽下载的示例文件。\n创建时间: " + new Date().toLocaleString(),
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type: "text/plain"
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},
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png: {
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name: "demo-image.png",
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// 这里使用一个实际存在的在线图片URL作为示例
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url: "https://via.placeholder.com/300x200/3498db/FFFFFF?text=Demo+Image",
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type: "image/png"
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},
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pdf: {
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name: "数据报告.pdf",
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// 使用一个简单的PDF数据URL作为示例（实际应用中应使用真实文件）
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content: "data:application/pdf;base64,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",
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type: "application/pdf"
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}
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};
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// 当前选中的文件类型
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let currentFileType = 'txt';
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// 显示状态消息
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function showStatus(message, type) {
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statusMessage.textContent = message;
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statusMessage.className = 'status-message ' + type;
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statusMessage.style.display = 'block';
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// 3秒后隐藏消息
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setTimeout(() => {
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statusMessage.style.display = 'none';
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}, 3000);
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}
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// 获取文件URL
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function getFileUrl(fileType) {
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if (fileType === 'png') {
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return files.png.url;
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} else if (fileType === 'pdf') {
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return files.pdf.content; // 使用base64数据URL
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} else {
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// 为文本文件创建Blob URL
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const blob = new Blob([files.txt.content], { type: files.txt.type });
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return URL.createObjectURL(blob);
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}
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}
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// 获取文件名
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function getFileName(fileType) {
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return files[fileType].name;
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}
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// 处理拖拽开始事件
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draggableElement.addEventListener('dragstart', function (e) {
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// 设置拖拽效果为"复制"
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e.dataTransfer.effectAllowed = 'copy';
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e.dataTransfer.setData('text/plain', '下载文件: ' + getFileName(currentFileType));
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// 添加拖拽视觉效果
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this.classList.add('drag-target');
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// 创建隐藏的下载链接
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const link = document.createElement('a');
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link.href = getFileUrl(currentFileType);
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link.download = getFileName(currentFileType);
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// 模拟点击触发下载
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document.body.appendChild(link);
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link.click();
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document.body.removeChild(link);
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// 显示成功消息
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showStatus(`"${getFileName(currentFileType)}" 下载已开始，请检查浏览器的下载列表`, 'success');
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// 如果是文本文件，需要释放Blob URL
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if (currentFileType === 'txt') {
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setTimeout(() => URL.revokeObjectURL(link.href), 100);
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}
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// 循环切换文件类型（用于演示多种文件）
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if (currentFileType === 'txt') {
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currentFileType = 'png';
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} else if (currentFileType === 'png') {
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currentFileType = 'pdf';
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} else {
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currentFileType = 'txt';
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}
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// 更新拖拽元素的提示文本
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updateDraggableText();
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});
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// 拖拽结束事件
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draggableElement.addEventListener('dragend', function () {
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this.classList.remove('drag-target');
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});
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// 更新拖拽元素的提示文本
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function updateDraggableText() {
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const fileTypeNames = {
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'txt': '文本文件',
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'png': '图片文件',
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'pdf': 'PDF文档'
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};
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const fileTypeElement = draggableElement.querySelector('p');
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if (fileTypeElement) {
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fileTypeElement.textContent = `下次拖拽将下载: ${getFileName(currentFileType)} (${fileTypeNames[currentFileType]})`;
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}
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}
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// 初始化文本
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updateDraggableText();
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// 添加文件类型选择功能
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const fileItems = document.querySelectorAll('.file-item');
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fileItems.forEach((item, index) => {
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item.addEventListener('click', function () {
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const types = ['txt', 'png', 'pdf'];
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currentFileType = types[index];
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updateDraggableText();
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// 高亮显示选中的文件
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fileItems.forEach(el => el.style.backgroundColor = '#f8f9fa');
|
|
this.style.backgroundColor = '#e3f2fd';
|
|
|
|
showStatus(`已选择 "${getFileName(currentFileType)}"，现在可以拖拽下载`, 'success');
|
|
});
|
|
});
|
|
|
|
// 默认选中第一个文件
|
|
if (fileItems.length > 0) {
|
|
fileItems[0].style.backgroundColor = '#e3f2fd';
|
|
}
|
|
});
|
|
</script>
|
|
</body>
|
|
|
|
</html> |