<a href="https://www.baidu.com" rel="external nofollow" download="baidu.html">下载</a>

function download(href, title) {
    const a = document.createElement('a');
    a.setAttribute('href', href);
    a.setAttribute('download', title);
    a.click();
}

// 下载图片
download('https://lzw.me/images/gravatar.gif', 'lzwme-gravatar');
// 下载一个连接
download('https://lzw.me', 'lzwme-index.html');

data:[<mediatype>][;base64],<data>

download('data:,Hello%2C%20World!', 'data-uris.txt');
download('data:text/plain;base64,SGVsbG8sIFdvcmxkIQ%3D%3D', 'data-uris.txt');

const content = 'Welcome to lzw.me!';
const blob = new Blob([content]);
const href = URL.createObjectURL(blob);
download(href, 'download-text.txt');
URL.revokeObjectURL(href);

/**
 * 通过创建 a dom 对象方式实现前端文件下载
 * @param href 要下载的内容链接。当定义了 toBlob 时，可以为纯文本或二进制数据(取决于 toBlob 格式
 * @param fileName 下载后的文件名称
 * @param toBlob 如设置该参数，则通过 blob 方式将 href 转换为要保存的文件内容，该参数将入参为 new Blob([href], toBlob) 的第二个参数
 * @example
 * ```js
 * saveAs('abc', 'abc.txt', {});
 * saveAs('data:,Hello%2C%20World!', 'hello.txt');
 * saveAs('https://lzw.me/images/avatar/lzwme-80x80.png', 'lzwme-logo.png');
 * ```
 */
export function saveAs(href: string | Blob, fileName"HTMLEvents");
 // evt.initEvent("click", false, false);
 // aLink.dispatchEvent(evt);
 if (isBlob) setTimeout(() => URL.revokeObjectURL(aLink.href), 100);
 return aLink;
}

const downloadAble = 'download' in document.createElement('a');

fetch('lzwme.txt', {
    isDownload: true,
    body: {
        data: new Blob('hi!')
    }
})

self.addEventListener('fetch', function(event) {
    const req = event.request;
    if (!req.headers.get('isDownload')) {
        retrun fetch(req);
    }
    const filename = encodeURIComponent(req.url);
    const contentType = req.headers.get('Content-Type') || 'application/force-download';
    const disposition = "inline;filename=" + filename + ";filename*=utf-8''" + filename
    const myBody = req.headers.get(body).data;
    event.respondWith(
        new Response(myBody, {
            headers: {
                'Content-Type': contentType,
                'Content-Disposition': disposition
            }
        })
    );
});

/** 前端下载/保存文件 */
function saveAs(href, fileName) {
  const isBlob = href instanceof Blob;
  const aLink = document.createElement('a');
  aLink.href = isBlob "htmlcode">

function fetchDownload(url, options = {}) {
  options = Object.assign({ credentials: 'include', method: 'get', headers: {} }, options);
  return fetch(url, options).then(response => {
    return response.blob().then(blob => {
      if (!blob || !blob.size) return Promise.reject('empty');
      // 从 Content-Disposition 中获取文件名示例
      const cd = response.headers.get('Content-Disposition');
      if (cd && cd.includes('fileName') && !options.fileName) options.fileName = cd.split('fileName=')[1];
      options.fileName = decodeURIComponent(options.fileName || 'download-file');
      saveAs(blob, options.fileName);
      return options.fileName;
    });
  });
}
// 测试
fetchDownload('https://lzw.me/images/avatar/lzwme-80x80.png', {
    // method: 'post',
    // headers: {
    //   'Content-Type': 'application/json'
    // },
    // body: JSON.stringify({
    //   pageSize: 100000,
    //   startPage: 0
    // })
  })


以上就是前端 javascript 实现文件下载的示例的详细内容，更多关于JavaScript 文件下载的资料请关注其它相关文章！