如何在Electron呈现的网页上调用JavaScript函数？

我正在尝试使用Electron(以前的Atom Shell)为Twitter编写一个包装器.

我的main.js文件(它看起来几乎与" Hello World "示例相同,我只是在一个地方更改了它):

var app = require('app');  // Module to control application life.
var BrowserWindow = require('browser-window');  // Module to create native browser window.

// Report crashes to our server.
require('crash-reporter').start();

// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the Javascript object is GCed.
var mainWindow = null;

// Quit when all windows are closed.
app.on('window-all-closed', function() {
  if (process.platform != 'darwin')
    app.quit();
});

// This method will be called when atom-shell has done everything
// initialization and ready for creating browser windows.
app.on('ready', function() {

  // Create the browser window.
  mainWindow = new BrowserWindow ({'width':1000,'height':600});
  // and load the index.html of the app.
  mainWindow.loadUrl('https://twitter.com');

  // Emitted when the window is closed.
  mainWindow.on('closed', function() {
    // Dereference the window object, usually you would store windows
    // in an array if your app supports multi windows, this is the time
    // when you should delete the corresponding element.
    mainWindow = null;
  });
});

$(document).ready(function() {
    alert("Hurray!");
});

...

app.on('ready', function() {

  ...

  mainWindow.webContents.on('did-finish-load', function() {
    mainWindow.webContents.executeJavascript("alert('Hello There!');");
  });

  ...

});

/path/to/electron-framework/electron /your/app/folder

/path/to/electron-framework/electron --debug=1234 /your/app/folder

...

app.on('ready', function() {

  ...

  mainWindow.webContents.on('did-finish-load', function() {
    mainWindow.webContents.executeJavascript("alert('Hello There!');");
  });

  ...

});

/path/to/electron-framework/electron /your/app/folder

/path/to/electron-framework/electron --debug=1234 /your/app/folder