js实现附件下载

function downloadFile(filename, content) {
    // 创建一个Blob对象，content可以是字符串、数组缓冲区等
    const blob = new Blob([content], { type: 'application/octet-stream' });
    
    // 创建一个a标签
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = filename;
    
    // 将a标签添加到DOM中并模拟点击
    document.body.appendChild(link);
    link.click();
    
    // 移除a标签并释放URL对象
    document.body.removeChild(link);
    URL.revokeObjectURL(link.href);
}

// 使用示例
downloadFile('example.txt', 'Hello, world!');

async function downloadFile(url, filename) {
    const response = await fetch(url);
    const blob = await response.blob();
    
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = filename;
    
    document.body.appendChild(link);
    link.click();
    
    document.body.removeChild(link);
    URL.revokeObjectURL(link.href);
}

// 使用示例
downloadFile('https://example.com/file.pdf', 'downloaded.pdf');

function downloadBase64File(filename, base64Data, mimeType) {
    const byteCharacters = atob(base64Data.split(',')[1]);
    const byteNumbers = new Array(byteCharacters.length);
    for (let i = 0; i < byteCharacters.length; i++) {
        byteNumbers[i] = byteCharacters.charCodeAt(i);
    }
    const byteArray = new Uint8Array(byteNumbers);
    const blob = new Blob([byteArray], { type: mimeType });
    
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = filename;
    
    document.body.appendChild(link);
    link.click();
    
    document.body.removeChild(link);
    URL.revokeObjectURL(link.href);
}

// 使用示例
const base64Data = 'data:text/plain;base64,SGVsbG8sIHdvcmxkIQ=='; // "Hello, world!"的Base64编码
downloadBase64File('example.txt', base64Data, 'text/plain');