网页js的怎么下载

<a href="path_to_file" download="desired_filename.ext">Download File</a>

function downloadFile(url, filename) {
    const link = document.createElement('a');
    link.href = url;
    link.download = filename || 'download';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
}

// 使用方法
downloadFile('path_to_file', 'desired_filename.ext');

function downloadBlob(data, filename, mimeType) {
    const blob = new Blob([data], { type: mimeType || 'application/octet-stream' });
    const url = URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = url;
    link.download = filename || 'download';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    URL.revokeObjectURL(url);
}

// 使用方法
const data = 'Hello, world!'; // 可以是任何字符串或ArrayBuffer
downloadBlob(data, 'hello.txt', 'text/plain');

async function fetchAndDownload(url, filename) {
    const response = await fetch(url);
    if (!response.ok) throw new Error('Network response was not ok');
    const blob = await response.blob();
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = filename || 'download';
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    URL.revokeObjectURL(link.href);
}

// 使用方法
fetchAndDownload('path_to_file', 'desired_filename.ext');