# webFrameMain

> Control web pages and iframes.

Process: [Main](../glossary.md#main-process)

The `webFrameMain` module can be used to lookup frames across existing
[`WebContents`](web-contents.md) instances. Navigation events are the common
use case.

```javascript
const { BrowserWindow, webFrameMain } = require('electron')

const win = new BrowserWindow({ width: 800, height: 1500 })
win.loadURL('https://twitter.com')

win.webContents.on(
  'did-frame-navigate',
  (event, url, isMainFrame, frameProcessId, frameRoutingId) => {
    const frame = webFrameMain.fromId(frameProcessId, frameRoutingId)
    if (frame) {
      const code = 'document.body.innerHTML = document.body.innerHTML.replaceAll("heck", "h*ck")'
      frame.executeJavaScript(code)
    }
  }
)
```

You can also access frames of existing pages by using the `mainFrame` property
of [`WebContents`](web-contents.md).

```javascript
const { BrowserWindow } = require('electron')

async function main () {
  const win = new BrowserWindow({ width: 800, height: 600 })
  await win.loadURL('https://reddit.com')

  const youtubeEmbeds = win.webContents.mainFrame.frames.filter((frame) => {
    try {
      const url = new URL(frame.url)
      return url.host === 'www.youtube.com'
    } catch {
      return false
    }
  })

  console.log(youtubeEmbeds)
}

main()
```

## Methods

These methods can be accessed from the `webFrameMain` module:

### `webFrameMain.fromId(processId, routingId)`

* `processId` Integer - An `Integer` representing the internal ID of the process which owns the frame.
* `routingId` Integer - An `Integer` representing the unique frame ID in the
  current renderer process. Routing IDs can be retrieved from `WebFrameMain`
  instances (`frame.routingId`) and are also passed by frame
  specific `WebContents` navigation events (e.g. `did-frame-navigate`).

Returns `WebFrameMain | undefined` - A frame with the given process and routing IDs,
or `undefined` if there is no WebFrameMain associated with the given IDs.

## Class: WebFrameMain

Process: [Main](../glossary.md#main-process)

### Instance Methods

#### `frame.executeJavaScript(code[, userGesture])`

* `code` String
* `userGesture` Boolean (optional) - Default is `false`.

Returns `Promise<unknown>` - A promise that resolves with the result of the executed
code or is rejected if execution throws or results in a rejected promise.

Evaluates `code` in page.

In the browser window some HTML APIs like `requestFullScreen` can only be
invoked by a gesture from the user. Setting `userGesture` to `true` will remove
this limitation.

#### `frame.reload()`

Returns `boolean` - Whether the reload was initiated successfully. Only results in `false` when the frame has no history.

#### `frame.send(channel, ...args)`

* `channel` String
* `...args` any[]

Send an asynchronous message to the renderer process via `channel`, along with
arguments. Arguments will be serialized with the [Structured Clone
Algorithm][SCA], just like [`postMessage`][], so prototype chains will not be
included. Sending Functions, Promises, Symbols, WeakMaps, or WeakSets will
throw an exception.

The renderer process can handle the message by listening to `channel` with the
[`ipcRenderer`](ipc-renderer.md) module.

#### `frame.postMessage(channel, message, [transfer])`

* `channel` String
* `message` any
* `transfer` MessagePortMain[] (optional)

Send a message to the renderer process, optionally transferring ownership of
zero or more [`MessagePortMain`][] objects.

The transferred `MessagePortMain` objects will be available in the renderer
process by accessing the `ports` property of the emitted event. When they
arrive in the renderer, they will be native DOM `MessagePort` objects.

For example:

```js
// Main process
const { port1, port2 } = new MessageChannelMain()
webContents.mainFrame.postMessage('port', { message: 'hello' }, [port1])

// Renderer process
ipcRenderer.on('port', (e, msg) => {
  const [port] = e.ports
  // ...
})
```

### Instance Properties

#### `frame.url` _Readonly_

A `string` representing the current URL of the frame.

#### `frame.top` _Readonly_

A `WebFrameMain | null` representing top frame in the frame hierarchy to which `frame`
belongs.

#### `frame.parent` _Readonly_

A `WebFrameMain | null` representing parent frame of `frame`, the property would be
`null` if `frame` is the top frame in the frame hierarchy.

#### `frame.frames` _Readonly_

A `WebFrameMain[]` collection containing the direct descendents of `frame`.

#### `frame.framesInSubtree` _Readonly_

A `WebFrameMain[]` collection containing every frame in the subtree of `frame`,
including itself. This can be useful when traversing through all frames.

#### `frame.frameTreeNodeId` _Readonly_

An `Integer` representing the id of the frame's internal FrameTreeNode
instance. This id is browser-global and uniquely identifies a frame that hosts
content. The identifier is fixed at the creation of the frame and stays
constant for the lifetime of the frame. When the frame is removed, the id is
not used again.

#### `frame.name` _Readonly_

A `String` representing the frame name.

#### `frame.osProcessId` _Readonly_

An `Integer` representing the operating system `pid` of the process which owns this frame.

#### `frame.processId` _Readonly_

An `Integer` representing the Chromium internal `pid` of the process which owns this frame.
This is not the same as the OS process ID; to read that use `frame.osProcessId`.

#### `frame.routingId` _Readonly_

An `Integer` representing the unique frame id in the current renderer process.
Distinct `WebFrameMain` instances that refer to the same underlying frame will
have the same `routingId`.
