如何使用浏览器扩展篡改网页中的JS 文件

"permissions": [
  ...
  "webRequest",
  "webRequestBlocking"
]

chrome.webRequest.onBeforeRequest.addListener(
  function(details){
    const { url } = details;
    if(/xxxx\.js/.test(url)){
      // 这个函数要同步返回，因此我们不能在这里篡改文件
      // 不过先返回一个“信标”，注入到 dom 里作为注入 JS 的凭据
      // secretPageId 确保页面对得上，不过这一点貌似是多余的
      const secretPageId = Date.now() + "--" + Math.random();
      const redirectUrl = `
        data:javascript,
        var node = document.createElement('div');
        node.id = 'secretPageId';
        node.innerHTML ="${secretPageId}";
        document.body.appendChild(node);
      `.replace(/\n/g, '');
      getAndChangeScript(url, secretPageId);
      return {
        redirectUrl
      }
    }
    return {
      redirectUrl: url,
    }
  }
);

async function getAndChangeScript(src, secretPageId){
  const scriptStr = await (await fetch(url)).text();
  const changedScript = scriptStr.replace(
    // 这里是特征码
    "e.filterNoNumber=Y;",
    // 修改后的特征码，替换到原文中去
    "window.signMaker = J;e.filterNoNumber=Y;"
  );
  scriptInjectBus.send(secretPageId, changedScript);
}

const scriptInjectBus = (function () {
  const listenQueue = [];
  const send = function (info) {
    listenQueue.forEach(function (handler) {
      handler(info);
    });
  };

  const listen = function (handler) {
    listenQueue.push(handler);
  };

  return {
    send,
    listen
  };
})();

chrome.tabs.onUpdated.addListener(function (tabId, changeInfo, tab) {
  scriptInjectBus.listen(function (info) {
    chrome.tabs.sendMessage(tab.id, info, function (res) {});
  });
});

chrome.runtime.onMessage.addListener(function(info){
    const node = document.getElementById('secretPageId');
    const secretPageId = node.innerHTML.trim();
    if(secretPageId && secretPageId === info.secretPageId){
        node.innerHTML = '';
        const scriptNode = document.createElement('script');
        scriptNode.innerHTML = info.js;
        document.body.appendChild(scriptNode);
    }
}