js下载大文件在哪里下载

function downloadLargeFile(url, chunkSize = 1024 * 1024) {
    const totalSize = 100 * 1024 * 1024; // 假设文件总大小为100MB
    let downloadedSize = 0;
    const chunks = Math.ceil(totalSize / chunkSize);
    const blobParts = [];

    function downloadChunk(index) {
        if (index >= chunks) {
            const blob = new Blob(blobParts);
            const link = document.createElement('a');
            link.href = URL.createObjectURL(blob);
            link.download = 'largefile.bin';
            link.click();
            return;
        }

        const start = index * chunkSize;
        const end = Math.min(start + chunkSize, totalSize);
        const xhr = new XMLHttpRequest();
        xhr.open('GET', url, true);
        xhr.setRequestHeader('Range', `bytes=${start}-${end - 1}`);
        xhr.responseType = 'blob';

        xhr.onload = () => {
            if (xhr.status === 206) { // Partial Content
                blobParts.push(xhr.response);
                downloadedSize += xhr.response.size;
                console.log(`Downloaded ${downloadedSize} of ${totalSize} bytes`);
                downloadChunk(index + 1);
            }
        };

        xhr.onerror = () => {
            console.error('Chunk download failed, retrying...');
            setTimeout(() => downloadChunk(index), 2000); // Retry after 2 seconds
        };

        xhr.send();
    }

    downloadChunk(0);
}

// 使用示例
downloadLargeFile('http://example.com/largefile.bin');