为什么这段代码不起作用?我正在创建一个 Firefox 扩展，但代码没有运行.但是，如果我将代码粘贴到控制台中，它就可以工作

when the extension loads it doesn't show any error, it seems like it just won't run

这是完整的代码

xhrScript.js

(function(){

    const proxiedOpen = XMLHttpRequest.prototype.open;
    window.XMLHttpRequest.prototype.open = function ( _, url) {
        this.__URL = url;
        return proxiedOpen.apply(this, arguments);
    };

    const proxiedSend = window.XMLHttpRequest.prototype.send;
    window.XMLHttpRequest.prototype.send = function () {
        const { protocol, host } = window.location;
        // showing only when it paste in console
        console.log("full request url ", `${protocol}//${host}${this.__URL}`);
        return proxiedSend.apply(this, [].slice.call(arguments));
    };

})();

// this works all times
document.body.style.border = "7px solid blue";

ma​​nifest.json

{
    "manifest_version": 2,
    "name": "XHR request urls",
    "version": "1.0",
    "description": "get all the request url's",

    "content_scripts": [
      {
        "matches": ["*://*/*"],
        "js": ["xhrScript.js"]
      }
    ]  
}

如您所见，最后一行是 document.body.style.border = "7px solid blue";，每次都可以正常工作.但是 XMLHttpRequest open 和 send 方法不起作用.仅当我将代码粘贴到控制台时才有效.

const urls = new WeakMap();
const origXhr = hookPagePrototype('XMLHttpRequest', {
  open(method, url) {
    urls.set(this, url);
    return origXhr.open.apply(this, arguments);
  },
  send() {
    console.log('Sending', new URL(urls.get(this), location).href);
    return origXhr.send.apply(this, arguments);
  },
});

function hookPagePrototype(protoName, funcs) {
  const proto = wrappedJSObject[protoName].prototype;
  const oldFuncs = {};
  for (const [name, fn] of Object.entries(funcs)) {
    oldFuncs[name] = exportFunction(proto[name], wrappedJSObject);
    proto[name] = exportFunction(fn, wrappedJSObject);
  }
  return oldFuncs;
}