dsanders11/index.html

## index.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; frame-src subframe://*">
    <link href="./styles.css" rel="stylesheet">
    <title>Hello World!</title>
  </head>
  <body>
    <h1>Hello World!</h1>
    We are using Node.js <span id="node-version"></span>,
    Chromium <span id="chrome-version"></span>,
    and Electron <span id="electron-version"></span>.

    <iframe id="subframe" src="subframe://index.html"></iframe>

    <script src="./renderer.js"></script>
  </body>
</html>

## main.js
// Modules to control application life and create native browser window
const {app, BrowserWindow, MessageChannelMain, protocol} = require('electron')
const path = require('path')

function createWindow () {
  // Create the browser window.
  const mainWindow = new BrowserWindow({
    width: 800,
    height: 600,
    webPreferences: {
      preload: path.join(__dirname, 'preload.js')
    }
  })

  const { port1, port2 } = new MessageChannelMain()

  // Send port along to the preload script
  mainWindow.webContents.on('did-finish-load', () => {
    mainWindow.webContents.mainFrame.postMessage('port', null, [port1])
    port2.on('message', (event) => {
      console.log(event)
    })
    port2.start()
  })

  // and load the index.html of the app.
  mainWindow.loadFile('index.html')
}

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.whenReady().then(() => {
  protocol.registerFileProtocol('subframe', (req, callback) => {
    if (req.url === 'subframe://index.html') {
      callback({ path: path.join(__dirname, 'subframe.html') })
    } else if (req.url === 'subframe://subrenderer.js') {
      callback({ path: path.join(__dirname, 'subrenderer.js') })
    } else {
      callback(404)
    }
  })

  createWindow()

  app.on('activate', function () {
    // On macOS it's common to re-create a window in the app when the
    // dock icon is clicked and there are no other windows open.
    if (BrowserWindow.getAllWindows().length === 0) createWindow()
  })
})

// Quit when all windows are closed, except on macOS. There, it's common
// for applications and their menu bar to stay active until the user quits
// explicitly with Cmd + Q.
app.on('window-all-closed', function () {
  if (process.platform !== 'darwin') app.quit()
})

## package.json
{
  "name": "milky-power-groan-dvhp2",
  "productName": "milky-power-groan-dvhp2",
  "description": "My Electron application description",
  "keywords": [],
  "main": "./main.js",
  "version": "1.0.0",
  "author": "dsanders11",
  "scripts": {
    "start": "electron ."
  },
  "dependencies": {},
  "devDependencies": {
    "electron": "22.0.0"
  }
}

## preload.js
const { ipcRenderer } = require('electron')

// Forward the port along to the iframe
ipcRenderer.on('port', e => {
  const port = e.ports[0]
  document.getElementById('subframe').contentWindow.postMessage('main-process', '*', [port])
})

/**
 * The preload script runs before. It has access to web APIs
 * as well as Electron's renderer process modules and some
 * polyfilled Node.js functions.
 *
 * https://www.electronjs.org/docs/latest/tutorial/sandbox
 */
window.addEventListener('DOMContentLoaded', () => {
  const replaceText = (selector, text) => {
    const element = document.getElementById(selector)
    if (element) element.innerText = text
  }

  for (const type of ['chrome', 'node', 'electron']) {
    replaceText(`${type}-version`, process.versions[type])
  }
})

## renderer.js
const { port1, port2 } = new MessageChannel()

port1.addEventListener('message', (event) => {
    const element = document.createElement('p')
    element.innerText = event.data
    document.body.appendChild(element)
})

window.addEventListener('load', () => {
    document.getElementById('subframe').contentWindow.postMessage('parent-frame', '*', [port2])
})

port1.start()

## styles.css
iframe {
    border: none;
}

## subframe.html
<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' subframe://*; style-src 'self' 'unsafe-inline'">
    <title>Hello World!</title>
  </head>
  <body>
    <h1>Subframe</h1>
    <script src="subframe://subrenderer.js"></script>
  </body>
</html>

## subrenderer.js
window.addEventListener("message", (event) => {
    // Use the port that was transferred to send a message
    if (event.data === 'main-process') {
        // To the main process, from this subframe
        event.ports[0].postMessage('hello main process from subframe')
    } else if (event.data === 'parent-frame') {
        // To our parent frame
        event.ports[0].postMessage('hello parent frame from subframe')
    }
})
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="UTF-8">
	<!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
	<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; frame-src subframe://*">
	<link href="./styles.css" rel="stylesheet">
	<title>Hello World!</title>
	</head>
	<body>
	<h1>Hello World!</h1>
	We are using Node.js <span id="node-version"></span>,
	Chromium <span id="chrome-version"></span>,
	and Electron <span id="electron-version"></span>.

	<iframe id="subframe" src="subframe://index.html"></iframe>

	<script src="./renderer.js"></script>
	</body>
	</html>
	// Modules to control application life and create native browser window
	const {app, BrowserWindow, MessageChannelMain, protocol} = require('electron')
	const path = require('path')

	function createWindow () {
	// Create the browser window.
	const mainWindow = new BrowserWindow({
	width: 800,
	height: 600,
	webPreferences: {
	preload: path.join(__dirname, 'preload.js')
	}
	})

	const { port1, port2 } = new MessageChannelMain()

	// Send port along to the preload script
	mainWindow.webContents.on('did-finish-load', () => {
	mainWindow.webContents.mainFrame.postMessage('port', null, [port1])
	port2.on('message', (event) => {
	console.log(event)
	})
	port2.start()
	})

	// and load the index.html of the app.
	mainWindow.loadFile('index.html')
	}

	// This method will be called when Electron has finished
	// initialization and is ready to create browser windows.
	// Some APIs can only be used after this event occurs.
	app.whenReady().then(() => {
	protocol.registerFileProtocol('subframe', (req, callback) => {
	if (req.url === 'subframe://index.html') {
	callback({ path: path.join(__dirname, 'subframe.html') })
	} else if (req.url === 'subframe://subrenderer.js') {
	callback({ path: path.join(__dirname, 'subrenderer.js') })
	} else {
	callback(404)
	}
	})

	createWindow()

	app.on('activate', function () {
	// On macOS it's common to re-create a window in the app when the
	// dock icon is clicked and there are no other windows open.
	if (BrowserWindow.getAllWindows().length === 0) createWindow()
	})
	})

	// Quit when all windows are closed, except on macOS. There, it's common
	// for applications and their menu bar to stay active until the user quits
	// explicitly with Cmd + Q.
	app.on('window-all-closed', function () {
	if (process.platform !== 'darwin') app.quit()
	})
	{
	"name": "milky-power-groan-dvhp2",
	"productName": "milky-power-groan-dvhp2",
	"description": "My Electron application description",
	"keywords": [],
	"main": "./main.js",
	"version": "1.0.0",
	"author": "dsanders11",
	"scripts": {
	"start": "electron ."
	},
	"dependencies": {},
	"devDependencies": {
	"electron": "22.0.0"
	}
	}
	const { ipcRenderer } = require('electron')

	// Forward the port along to the iframe
	ipcRenderer.on('port', e => {
	const port = e.ports[0]
	document.getElementById('subframe').contentWindow.postMessage('main-process', '*', [port])
	})

	/**
	* The preload script runs before. It has access to web APIs
	* as well as Electron's renderer process modules and some
	* polyfilled Node.js functions.
	*
	* https://www.electronjs.org/docs/latest/tutorial/sandbox
	*/
	window.addEventListener('DOMContentLoaded', () => {
	const replaceText = (selector, text) => {
	const element = document.getElementById(selector)
	if (element) element.innerText = text
	}

	for (const type of ['chrome', 'node', 'electron']) {
	replaceText(`${type}-version`, process.versions[type])
	}
	})
	const { port1, port2 } = new MessageChannel()

	port1.addEventListener('message', (event) => {
	const element = document.createElement('p')
	element.innerText = event.data
	document.body.appendChild(element)
	})

	window.addEventListener('load', () => {
	document.getElementById('subframe').contentWindow.postMessage('parent-frame', '*', [port2])
	})

	port1.start()
	window.addEventListener("message", (event) => {
	// Use the port that was transferred to send a message
	if (event.data === 'main-process') {
	// To the main process, from this subframe
	event.ports[0].postMessage('hello main process from subframe')
	} else if (event.data === 'parent-frame') {
	// To our parent frame
	event.ports[0].postMessage('hello parent frame from subframe')
	}
	})