webContents
- 方法
- 类: WebContents

webContents

渲染以及控制 web 页面

webContents 是一个 EventEmitter。负责渲染和控制网页, 是 BrowserWindow 对象的一个属性。这是一个访问 webContents 对象的例子:

const { BrowserWindow } = require('electron')
const win = new BrowserWindow({ width: 800, height: 1500 })
win.loadURL('http://github.com')
const contents = win.webContents
console.log(contents)

方法

通过webContents模块可以访问以下方法：

const { webContents } = require('electron')
console.log(webContents)

`webContents.getAllWebContents()`

返回 WebContents[] - 所有 WebContents 实例的数组。包含所有Windows，webviews，opened devtools 和 devtools 扩展背景页的 web 内容

`webContents.getFocusedWebContents()`

Returns WebContents - 此 app 中焦点的 web 内容，否则返回 null。

`webContents.fromId(id)`

id Integer

Returns WebContents | undefined - A WebContents instance with the given ID, or undefined if there is no WebContents associated with the given ID.

类: WebContents

渲染和控制 BrowserWindow 实例的内容。

进程：主进程

实例事件

Event: ‘did-fail-load’

event Event
errorCode Integer
errorDescription String
validatedURL String
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

这个事件类似于 did-finish-load ，只不过是在加载失败之后触发。完整的错误码列表以及含义，请看这

Event: ‘did-fail-provisional-load’

event Event
errorCode Integer
errorDescription String
validatedURL String
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

这个事件类似于 did-finish-load，只不过是在加载失败或取消加载之后触发，例如调用 window.stop() 。

Event: ‘did-frame-finish-load’

event Event
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

当框架完成导航（navigation）时触发

事件： ‘page-title-updated’

event Event
title String
explicitSet Boolean

Fired when page title is set during navigation. explicitSet is false when title is synthesized from file url.

事件: ‘page-favicon-updated’

event Event
favicons String[] - 由连接组成的数组。

当页面获取到favicon的连接时，触发该事件。

Event: ‘new-window’ Deprecated

event NewWindowWebContentsEvent
url String
frameName String
disposition String - 可以被设置为 default, foreground-tab, background-tab, new-window, save-to-disk 及 other.
options BrowserWindowConstructorOptions - 用于创建新的 BrowserWindow.
additionalFeatures String[] - 非标准功能(非标准功能是指这些功能不是由Chromium或Electron处理的功能)，这些功能默认指向window.open().
referrer Referrer - The referrer that will be passed to the new window. May or may not result in the Referer header being sent, depending on the referrer policy.
postBody PostBody (optional) - The post data that will be sent to the new window, along with the appropriate headers that will be set. If no post data is to be sent, the value will be null. Only defined when the window is being created by a form that set target=_blank.

已弃用：webContents.setWindowOpenHandler。

Emitted when the page requests to open a new window for a url. It could be requested by window.open or an external link like <a target='_blank'>.

默认情况下, 将为 url 创建新的 BrowserWindow。

调用event.preventDefault()事件，可以阻止Electron自动创建新的BrowserWindow实例。调用event.preventDefault() 事件后，你还可以手动创建新的BrowserWindow实例，不过接下来你必须用event.newGuest方法来引用BrowserWindow实例，如果你不这样做，则可能会产生异常。例如：

myBrowserWindow.webContents.on('new-window', (event, url, frameName, disposition, options, additionalFeatures, referrer, postBody) => {
  event.preventDefault()
  const win = new BrowserWindow({
    webContents: options.webContents, // use existing webContents if provided
    show: false
  })
  win.once('ready-to-show', () => win.show())
  if (!options.webContents) {
    const loadOptions = {
      httpReferrer: referrer
    }
    if (postBody != null) {
      const { data, contentType, boundary } = postBody
      loadOptions.postData = postBody.data
      loadOptions.extraHeaders = `content-type: ${contentType}; boundary=${boundary}`
    }
    win.loadURL(url, loadOptions) // existing webContents will be navigated automatically
  }
  event.newGuest = win
})

Event: ‘did-create-window’

window BrowserWindow
details Object
- url String - URL for the created window.
- frameName String - Name given to the created window in the window.open() call.
- options BrowserWindowConstructorOptions - The options used to create the BrowserWindow. They are merged in increasing precedence: options inherited from the parent, parsed options from the features string from window.open(), and options given by webContents.setWindowOpenHandler. Unrecognized options are not filtered out.
- additionalFeatures String[] - The non-standard features (features not handled Chromium or Electron) Deprecated
- referrer Referrer - The referrer that will be passed to the new window. May or may not result in the Referer header being sent, depending on the referrer policy.
- postBody PostBody (optional) - The post data that will be sent to the new window, along with the appropriate headers that will be set. If no post data is to be sent, the value will be null. Only defined when the window is being created by a form that set target=_blank.
- disposition String - Can be default, foreground-tab, background-tab, new-window, save-to-disk and other.

Emitted after successful creation of a window via window.open in the renderer. Not emitted if the creation of the window is canceled from webContents.setWindowOpenHandler.

See window.open() for more details and how to use this in conjunction with webContents.setWindowOpenHandler.

Event: ‘will-navigate’

event Event
url String

Emitted when a user or the page wants to start navigation. It can happen when the window.location object is changed or a user clicks a link in the page.

This event will not emit when the navigation is started programmatically with APIs like webContents.loadURL and webContents.back.

It is also not emitted for in-page navigations, such as clicking anchor links or updating the window.location.hash. Use did-navigate-in-page event for this purpose.

调用event.preventDefault()将阻止导航。

Event: ‘did-start-navigation’

event Event
url String
isInPlace Boolean
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

Emitted when any frame (including main) starts navigating. isInPlace will be true for in-page navigations.

Event: ‘will-redirect’

event Event
url String
isInPlace Boolean
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

Emitted as a server side redirect occurs during navigation. For example a 302 redirect.

This event will be emitted after did-start-navigation and always before the did-redirect-navigation event for the same navigation.

Calling event.preventDefault() will prevent the navigation (not just the redirect).

Event: ‘did-redirect-navigation’

event Event
url String
isInPlace Boolean
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

Emitted after a server side redirect occurs during navigation. For example a 302 redirect.

This event cannot be prevented, if you want to prevent redirects you should checkout out the will-redirect event above.

Event: ‘did-navigate’

event Event
url String
httpResponseCode Integer - -1 for non HTTP navigations
httpStatusText String - empty for non HTTP navigations

Emitted when a main frame navigation is done.

This event is not emitted for in-page navigations, such as clicking anchor links or updating the window.location.hash. Use did-navigate-in-page event for this purpose.

Event: ‘did-frame-navigate’

event Event
url String
httpResponseCode Integer - -1 for non HTTP navigations
httpStatusText String - empty for non HTTP navigations,
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

Emitted when any frame navigation is done.

This event is not emitted for in-page navigations, such as clicking anchor links or updating the window.location.hash. Use did-navigate-in-page event for this purpose.

Event: ‘did-navigate-in-page’

event Event
url String
isMainFrame Boolean
frameProcessId Integer
frameRoutingId Integer

Emitted when an in-page navigation happened in any frame.

当发生页内导航时，虽然页面地址发生变化，但它并没有导航到其它页面。例如，点击锚点链接，或者DOM的 hashchange事件被触发时，都会触发该事件。

Event: ‘will-prevent-unload’

event Event

Emitted when a beforeunload event handler is attempting to cancel a page unload.

Calling event.preventDefault() will ignore the beforeunload event handler and allow the page to be unloaded.

const { BrowserWindow, dialog } = require('electron')
const win = new BrowserWindow({ width: 800, height: 600 })
win.webContents.on('will-prevent-unload', (event) => {
  const choice = dialog.showMessageBoxSync(win, {
    type: 'question',
    buttons: ['Leave', 'Stay'],
    title: 'Do you want to leave this site?',
    message: 'Changes you made may not be saved.',
    defaultId: 0,
    cancelId: 1
  })
  const leave = (choice === 0)
  if (leave) {
    event.preventDefault()
  }
})

Event: ‘crashed’ Deprecated

event Event
killed Boolean

当渲染进程崩溃或被结束时触发

已废弃： 此事件被包含更多关于渲染过程为何消失的信息的 render-process-gone 事件替代了 It isn’t always because it crashed. The killed boolean can be replaced by checking reason === 'killed' when you switch to that event.

Event: ‘render-process-gone’

event Event
details Object
- reason String - The reason the render process is gone. 可选值：
  - clean-exit - Process exited with an exit code of zero
  - abnormal-exit - Process exited with a non-zero exit code
  - killed - Process was sent a SIGTERM or otherwise killed externally
  - crashed - Process crashed
  - oom - Process ran out of memory
  - launch-failed - Process never successfully launched
  - integrity-failure - Windows code integrity checks failed
- exitCode Integer - The exit code of the process, unless reason is launch-failed, in which case exitCode will be a platform-specific launch failure error code.

Emitted when the renderer process unexpectedly disappears. This is normally because it was crashed or killed.

Event: ‘plugin-crashed’

event Event
name String
version String

当有插件进程崩溃时触发

Event: ‘before-input-event’

event Event
input Object - Input properties.
- type String - 可以是 keyUp ，或者 keyDown.
- key String - 等同于 KeyboardEvent.key.
- code String - 等同于 KeyboardEvent. code .
- isAutoRepeat String - 等同于 KeyboardEvent. repeat .
- isComposing Boolean - Equivalent to KeyboardEvent.isComposing.
- shift String - 等同于 KeyboardEvent.shiftKey .
- control String - 等同于 KeyboardEvent. controlKey .
- alt String - 等同于 KeyboardEvent. altKey .
- meta String - 等同于 KeyboardEvent. metaKey .

Emitted before dispatching the keydown and keyup events in the page. Calling event.preventDefault will prevent the page keydown/keyup events and the menu shortcuts.

To only prevent the menu shortcuts, use setIgnoreMenuShortcuts:

const { BrowserWindow } = require('electron')
const win = new BrowserWindow({ width: 800, height: 600 })
win.webContents.on('before-input-event', (event, input) => {
  // For example, only enable application menu keyboard shortcuts when
  // Ctrl/Cmd are down.
  win.webContents.setIgnoreMenuShortcuts(!input.control && !input.meta)
})

Event: ‘zoom-changed’

event Event
zoomDirection String - Can be in or out.

Emitted when the user is requesting to change the zoom level using the mouse wheel.

事件: ‘certificate-error’

event Event
url String
error String - 错误码.
certificate 证书
callback Function
- isTrusted Boolean - 用于显示证书是否可信。

证书的链接验证失败时，触发该事件。

使用方式与app的certificate-error的事件相同。

事件: ‘select-client-certificate’

event Event
url URL
certificateList 证书[]
callback Function
- certificate Certificate - Must be a certificate from the given list.

当一个客户证书被请求的时候发出。

使用方式与app的select-client-certificate的事件相同。

事件: “login”

event Event
authenticationResponseDetails Object
- url URL
authInfo Object
- isProxy Boolean
- scheme String
- host String
- port Integer
- realm String
callback Function
- username String (optional)
- password String (optional)

当 webContents 要进行基本身份验证时触发。

使用方式与app的login的事件相同。

Event: ‘found-in-page’

event Event
result Object
- requestId Integer
- activeMatchOrdinal Integer - 当前匹配位置。
- matches Integer - 符合匹配条件的元素个数。
- selectionArea Rectangle - Coordinates of first match region.
- finalUpdate Boolean

如果调用[webContents.findInPage]有返回时，会触发这一事件。

Event: ‘media-started-playing’

多媒体开始播放时，触发该事件。

Event: ‘did-change-theme-color’

event Event
color (String | null) - Theme color is in format of ‘#rrggbb’. It is null when no theme color is set.

Emitted when a page’s theme color changes. This is usually due to encountering a meta tag:

<meta name='theme-color' content='#ff0000'>

Event: ‘update-target-url’

event Event
url String

当鼠标滑到，或者键盘切换到a连接时，触发该事件。

Event: ‘cursor-changed’

event Event
type String
image NativeImage (可选)
scale Float (optional) - scaling factor for the custom cursor.
size Size (可选) - image大小。
hotspot Point (optional) - coordinates of the custom cursor’s hotspot.

当鼠标指针改变的时候触发。 Type参数值包含：default, crosshair, pointer, text, wait, help, e-resize, n-resize, ne-resize, nw-resize, s-resize, se-resize, sw-resize, w-resize, ns-resize, ew-resize, nesw-resize, nwse-resize, col-resize, row-resize, m-panning, e-panning, n-panning, ne-panning, nw-panning, s-panning, se-panning, sw-panning, w-panning, move, vertical-text, cell, context-menu, alias, progress, nodrop, copy, none, not-allowed, zoom-in, zoom-out, grab, grabbing 或 custom.

If the type parameter is custom, the image parameter will hold the custom cursor image in a NativeImage, and scale, size and hotspot will hold additional information about the custom cursor.

Event: ‘context-menu’

event Event
params Object
- x Integer - x 坐标。
- y Integer - y 坐标。
- linkURL String - URL of the link that encloses the node the context menu was invoked on.
- linkText String - Text associated with the link. May be an empty string if the contents of the link are an image.
- pageURL String - URL of the top level page that the context menu was invoked on.
- frameURL String - URL of the subframe that the context menu was invoked on.
- srcURL String - Source URL for the element that the context menu was invoked on. Elements with source URLs are images, audio and video.
- mediaType String - Type of the node the context menu was invoked on. Can be none, image, audio, video, canvas, file or plugin.
- hasImageContents Boolean - Whether the context menu was invoked on an image which has non-empty contents.
- isEditable Boolean - Whether the context is editable.
- selectionText String - Text of the selection that the context menu was invoked on.
- titleText String - Title or alt text of the selection that the context was invoked on.
- misspelledWord String - The misspelled word under the cursor, if any.
- dictionarySuggestions String[] - An array of suggested words to show the user to replace the misspelledWord. Only available if there is a misspelled word and spellchecker is enabled.
- frameCharset String - The character encoding of the frame on which the menu was invoked.
- inputFieldType String - If the context menu was invoked on an input field, the type of that field. Possible values are none, plainText, password, other.
- menuSourceType String - Input source that invoked the context menu. Can be none, mouse, keyboard, touch or touchMenu.
- mediaFlags Object - The flags for the media element the context menu was invoked on.
  - inError Boolean - Whether the media element has crashed.
  - isPaused Boolean - Whether the media element is paused.
  - isMuted Boolean - Whether the media element is muted.
  - hasAudio Boolean - Whether the media element has audio.
  - isLooping Boolean - Whether the media element is looping.
  - isControlsVisible Boolean - Whether the media element’s controls are visible.
  - canToggleControls Boolean - Whether the media element’s controls are toggleable.
  - canRotate Boolean - Whether the media element can be rotated.
- editFlags Object - These flags indicate whether the renderer believes it is able to perform the corresponding action.
  - canUndo Boolean - Whether the renderer believes it can undo.
  - canRedo Boolean - Whether the renderer believes it can redo.
  - canCut Boolean - Whether the renderer believes it can cut.
  - canCopy Boolean - Whether the renderer believes it can copy
  - canPaste Boolean - Whether the renderer believes it can paste.
  - canDelete Boolean - Whether the renderer believes it can delete.
  - canSelectAll Boolean - Whether the renderer believes it can select all.

Emitted when there is a new context menu that needs to be handled.

事件: ‘select-bluetooth-device’

event Event
devices BluetoothDevice[]
callback Function
- deviceId String 设备Id

Emitted when bluetooth device needs to be selected on call to navigator.bluetooth.requestDevice. To use navigator.bluetooth api webBluetooth should be enabled. If event.preventDefault is not called, first available device will be selected. callback should be called with deviceId to be selected, passing empty string to callback will cancel the request.

const { app, BrowserWindow } = require('electron')
let win = null
app.commandLine.appendSwitch('enable-experimental-web-platform-features')
app.whenReady().then(() => {
  win = new BrowserWindow({ width: 800, height: 600 })
  win.webContents.on('select-bluetooth-device', (event, deviceList, callback) => {
    event.preventDefault()
    const result = deviceList.find((device) => {
      return device.deviceName === 'test'
    })
    if (!result) {
      callback('')
    } else {
      callback(result.deviceId)
    }
  })
})

Event: ‘paint’

event Event
dirtyRect Rectangle
image NativeImage - The image data of the whole frame.

Emitted when a new frame is generated. Only the dirty area is passed in the buffer.

const { BrowserWindow } = require('electron')
const win = new BrowserWindow({ webPreferences: { offscreen: true } })
win.webContents.on('paint', (event, dirty, image) => {
  // updateBitmap(dirty, image.getBitmap())
})
win.loadURL('http://github.com')

Event: ‘devtools-reload-page’

当在开发者工具中命令webContents重新加载时，触发该事件。

Event: ‘will-attach-webview’

event Event
webPreferences WebPreferences - The web preferences that will be used by the guest page. This object can be modified to adjust the preferences for the guest page.
params Record<string, string> - The other <webview> parameters such as the src URL. This object can be modified to adjust the parameters of the guest page.

Emitted when a <webview>‘s web contents is being attached to this web contents. Calling event.preventDefault() will destroy the guest page.

This event can be used to configure webPreferences for the webContents of a <webview> before it’s loaded, and provides the ability to set settings that can’t be set via <webview> attributes.

Note: The specified preload script option will appear as preloadURL (not preload) in the webPreferences object emitted with this event.

Event: ‘did-attach-webview’

event Event
webContents WebContents - The guest web contents that is used by the <webview>.

当<webview>被挂载到页面内容中时，触发该事件。

Event: ‘console-message’

event Event
level Integer - The log level, from 0 to 3. In order it matches verbose, info, warning and error.
message String - The actual console message
line Integer - The line number of the source that triggered this console message
sourceId String

Emitted when the associated window logs a console message.

Event: ‘preload-error’

event Event
preloadPath String
error Error

Emitted when the preload script preloadPath throws an unhandled exception error.

Event: ‘ipc-message’

event Event
channel String
...args any[]

Emitted when the renderer process sends an asynchronous message via ipcRenderer.send().

Event: ‘ipc-message-sync’

event Event
channel String
...args any[]

Emitted when the renderer process sends a synchronous message via ipcRenderer.sendSync().

事件: ‘desktop-capturer-get-sources’

event Event

Emitted when desktopCapturer.getSources() is called in the renderer process. Calling event.preventDefault() will make it return empty sources.

Event: ‘remote-require’ Deprecated

event IpcMainEvent
moduleName String

Emitted when remote.require() is called in the renderer process. 调用 event.preventDefault() 将阻止模块返回。可以通过设置 event.returnValue 返回自定义值。

Event: ‘remote-get-global’ Deprecated

event IpcMainEvent
globalName String

Emitted when remote.getGlobal() is called in the renderer process. 调用 event.preventDefault() 将阻止全局返回。可以通过设置 event.returnValue 返回自定义值。

Event: ‘remote-get-builtin’ Deprecated

event IpcMainEvent
moduleName String

Emitted when remote.getBuiltin() is called in the renderer process. 调用 event.preventDefault() 将阻止模块返回。可以通过设置 event.returnValue 返回自定义值。

Event: ‘remote-get-current-window’ Deprecated

event IpcMainEvent

Emitted when remote.getCurrentWindow() is called in the renderer process. 调用 event.preventDefault() 将阻止对象返回可以通过设置 event.returnValue 返回自定义值。

Event: ‘remote-get-current-web-contents’ Deprecated

event IpcMainEvent

Emitted when remote.getCurrentWebContents() is called in the renderer process. 调用 event.preventDefault() 将阻止对象返回可以通过设置 event.returnValue 返回自定义值。

Event: ‘preferred-size-changed’

event Event
preferredSize Size - The minimum size needed to contain the layout of the document—without requiring scrolling.

Emitted when the WebContents preferred size has changed.

This event will only be emitted when enablePreferredSizeMode is set to true in webPreferences.

实例方法

`contents.loadURL(url[, options])`

url String
options Object (可选)
- httpReferrer (String | Referrer) (可选) - 一个 HTTP Referrer url。
- userAgent String (可选) - 发起请求的 userAgent.
- extraHeaders String (optional) - Extra headers separated by “\n”.
- postData (UploadRawData[] | UploadFile[]) (optional)
- baseURLForDataURL String (可选) - 要加载的数据文件的根 url(带有路径分隔符). 只有当指定的 url是一个数据 url 并需要加载其他文件时，才需要这样做。

Returns Promise<void> - the promise will resolve when the page has finished loading (see did-finish-load), and rejects if the page fails to load (see did-fail-load). A noop rejection handler is already attached, which avoids unhandled rejection errors.

Loads the url in the window. The url must contain the protocol prefix, e.g. the http:// or file://. If the load should bypass http cache then use the pragma header to achieve it.

const { webContents } = require('electron')
const options = { extraHeaders: 'pragma: no-cache\n' }
webContents.loadURL('https://github.com', options)

`contents.loadFile(filePath[, options])`

filePath String
options Object (可选)
- query Record<String, String> (optional) - Passed to url.format().
- search String (可选) - 传递给 url.format().
- hash String (可选) - 传递给 url.format().

Returns Promise<void> - the promise will resolve when the page has finished loading (see did-finish-load), and rejects if the page fails to load (see did-fail-load).

Loads the given file in the window, filePath should be a path to an HTML file relative to the root of your application. For instance an app structure like this:

| root
| - package.json
| - src
|   - main.js
|   - index.html

需要运行以下代码：

win.loadFile('src/index.html')

`contents.downloadURL(url)`

url String

Initiates a download of the resource at url without navigating. The will-download event of session will be triggered.

`contents.getURL()`

Returns String - 当前页面的URL.

const { BrowserWindow } = require('electron')
const win = new BrowserWindow({ width: 800, height: 600 })
win.loadURL('http://github.com').then(() => {
  const currentURL = win.webContents.getURL()
  console.log(currentURL)
})

`contents.getTitle()`

返回 String - 当前页面的标题.

`contents.isDestroyed()`

返回 Boolean -判断页面是否被销毁

`contents.focus()`

页面聚焦

`contents.isFocused()`

返回 Boolean - 判断页面是否聚焦

`contents.isLoading()`

返回 Boolean - 判断页面是否正在加载资源

`contents.isLoadingMainFrame()`

Returns Boolean - Whether the main frame (and not just iframes or frames within it) is still loading.

`contents.isWaitingForResponse()`

Returns Boolean - Whether the web page is waiting for a first-response from the main resource of the page.

`contents.stop()`

Stops any pending navigation.

`contents.reload()`

刷新当前页面

`contents.reloadIgnoringCache()`

忽略缓存强制刷新页面

`contents.canGoBack()`

返回Boolean，是否可以返回到上一个页面

`contents.canGoForward()`

返回Boolean ，是否可以进入下一个页面

`contents.canGoToOffset(offset)`

offset Integer

Returns Boolean - Whether the web page can go to offset.

`contents.clearHistory()`

Clears the navigation history.

`contents.goBack()`

使浏览器回退到上一个页面。

`contents.goForward()`

使浏览器前进到下一个页面。

`contents.goToIndex(index)`

index Integer

Navigates browser to the specified absolute web page index.

`contents.goToOffset(offset)`

offset Integer

定位到相对于“当前入口”的指定的偏移。

`contents.isCrashed()`

Returns Boolean - Whether the renderer process has crashed.

`contents.forcefullyCrashRenderer()`

Forcefully terminates the renderer process that is currently hosting this webContents. This will cause the render-process-gone event to be emitted with the reason=killed || reason=crashed. Please note that some webContents share renderer processes and therefore calling this method may also crash the host process for other webContents as well.

Calling reload() immediately after calling this method will force the reload to occur in a new process. This should be used when this process is unstable or unusable, for instance in order to recover from the unresponsive event.

contents.on('unresponsive', async () => {
  const { response } = await dialog.showMessageBox({
    message: 'App X has become unresponsive',
    title: 'Do you want to try forcefully reloading the app?',
    buttons: ['OK', 'Cancel'],
    cancelId: 1
  })
  if (response === 0) {
    contents.forcefullyCrashRenderer()
    contents.reload()
  }
})

`contents.setUserAgent(userAgent)`

userAgent String

重写该页面的user agent

`contents.getUserAgent()`

返回 String - 当前页面的user agent.

`contents.insertCSS(css[, options])`

css String
options Object (可选)
- cssOrigin String (optional) - Can be either ‘user’ or ‘author’; Specifying ‘user’ enables you to prevent websites from overriding the CSS you insert. Default is ‘author’.

Returns Promise<String> - A promise that resolves with a key for the inserted CSS that can later be used to remove the CSS via contents.removeInsertedCSS(key).

Injects CSS into the current web page and returns a unique key for the inserted stylesheet.

contents.on('did-finish-load', () => {
  contents.insertCSS('html, body { background-color: #f00; }')
})

`contents.removeInsertedCSS(key)`

key String

Returns Promise<void> - Resolves if the removal was successful.

Removes the inserted CSS from the current web page. The stylesheet is identified by its key, which is returned from contents.insertCSS(css).

contents.on('did-finish-load', async () => {
  const key = await contents.insertCSS('html, body { background-color: #f00; }')
  contents.removeInsertedCSS(key)
})

`contents.executeJavaScript(code[, userGesture])`

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

Returns Promise<any> - A promise that resolves with the result of the executed code or is rejected if the result of the code is a rejected promise.

在页面中执行 code。

在浏览器窗口中，一些HTML API（如requestFullScreen）只能是由来自用户的手势调用。将 userGesture 设置为 true 将删除此限制。

Code execution will be suspended until web page stop loading.

contents.executeJavaScript('fetch("https://jsonplaceholder.typicode.com/users/1").then(resp => resp.json())', true)
  .then((result) => {
    console.log(result) // Will be the JSON object from the fetch call
  })

`contents.executeJavaScriptInIsolatedWorld(worldId, scripts[, userGesture])`

worldId Integer - The ID of the world to run the javascript in, 0 is the default world, 999 is the world used by Electron’s contextIsolation feature. You can provide any integer here.
scripts WebSource[]
userGesture Boolean (optional) - Default is false.

Returns Promise<any> - A promise that resolves with the result of the executed code or is rejected if the result of the code is a rejected promise.

Works like executeJavaScript but evaluates scripts in an isolated context.

`contents.setIgnoreMenuShortcuts(ignore)`

ignore Boolean

Ignore application menu shortcuts while this web contents is focused.

`contents.setWindowOpenHandler(handler)`

handler Function<{action: ‘deny’} | {action: ‘allow’, overrideBrowserWindowOptions?: BrowserWindowConstructorOptions}>
- details Object
  - url String - The resolved version of the URL passed to window.open(). e.g. opening a window with window.open('foo') will yield something like https://the-origin/the/current/path/foo.
  - frameName String - Name of the window provided in window.open()
  - features String - Comma separated list of window features provided to window.open(). Returns {action: 'deny'} | {action: 'allow', overrideBrowserWindowOptions?: BrowserWindowConstructorOptions} - deny cancels the creation of the new window. allow will allow the new window to be created. Specifying overrideBrowserWindowOptions allows customization of the created window. Returning an unrecognized value such as a null, undefined, or an object without a recognized ‘action’ value will result in a console error and have the same effect as returning {action: 'deny'}.

Called before creating a window when window.open() is called from the renderer. See window.open() for more details and how to use this in conjunction with did-create-window.

`contents.setAudioMuted(muted)`

muted Boolean

使当前页面音频静音

`contents.isAudioMuted()`

返回 Boolean -判断页面是否被静音

`contents.isCurrentlyAudible()`

Returns Boolean - Whether audio is currently playing.

`contents.setZoomFactor(factor)`

factor Double - Zoom factor; default is 1.0.

Changes the zoom factor to the specified factor. Zoom factor is zoom percent divided by 100, so 300% = 3.0.

The factor must be greater than 0.0.

`contents.getZoomFactor()`

Returns Number - the current zoom factor.

`contents.setZoomLevel(level)`

level Number - 缩放等级。

更改缩放等级。 The original size is 0 and each increment above or below represents zooming 20% larger or smaller to default limits of 300% and 50% of original size, respectively. The formula for this is scale := 1.2 ^ level.

NOTE: The zoom policy at the Chromium level is same-origin, meaning that the zoom level for a specific domain propagates across all instances of windows with the same domain. Differentiating the window URLs will make zoom work per-window.

`contents.getZoomLevel()`

Returns Number - the current zoom level.

`contents.setVisualZoomLevelLimits(minimumLevel, maximumLevel)`

minimumLevel Number
maximumLevel Number

Returns Promise<void>

设置最大和最小缩放级别。

NOTE: Visual zoom is disabled by default in Electron. To re-enable it, call:

js contents.setVisualZoomLevelLimits(1, 3)

`contents.undo()`

在页面中执行undo编辑命令。

`contents.redo()`

在页面中执行redo编辑命令。

`contents.cut()`

在页面中执行cut编辑命令。

`contents.copy()`

在页面中执行copy编辑命令。

`contents.copyImageAt(x, y)`

x Integer
y Integer

Copy the image at the given position to the clipboard.

`contents.paste()`

在页面中执行paste编辑命令。

`contents.pasteAndMatchStyle()`

在页面中执行pasteAndMatchStyle编辑命令。

`contents.delete()`

在页面中执行delete编辑命令。

`contents.selectAll()`

在页面中执行selectAll编辑命令。

`contents.unselect()`

在页面中执行unselect编辑命令。

`contents.replace(text)`

text String

在页面中执行replace编辑命令。

`contents.replaceMisspelling(text)`

text String

在页面中执行replaceMisspelling编辑命令。

`contents.insertText(text)`

text String

Returns Promise<void>

插入text 到焦点元素

`contents.findInPage(text[, options])`

text String - 要搜索的内容，必须非空。
options Object (可选)
- forward Boolean (可选) -向前或向后搜索，默认为 true。
- findNext Boolean (optional) - Whether the operation is first request or a follow up, defaults to false.
- matchCase Boolean (optional) - Whether search should be case-sensitive, defaults to false.

Returns Integer - The request id used for the request.

Starts a request to find all matches for the text in the web page. The result of the request can be obtained by subscribing to found-in-page event.

`contents.stopFindInPage(action)`

action String - Specifies the action to take place when ending [webContents.findInPage] request.
- clearSelection - Clear the selection.
- keepSelection - Translate the selection into a normal selection.
- activateSelection - Focus and click the selection node.

Stops any findInPage request for the webContents with the provided action.

const { webContents } = require('electron')
webContents.on('found-in-page', (event, result) => {
  if (result.finalUpdate) webContents.stopFindInPage('clearSelection')
})
const requestId = webContents.findInPage('api')
console.log(requestId)

`contents.capturePage([rect])`

rect Rectangle (optional) - The area of the page to be captured.

Returns Promise<NativeImage> - Resolves with a NativeImage

Captures a snapshot of the page within rect. Omitting rect will capture the whole visible page.

`contents.isBeingCaptured()`

Returns Boolean - Whether this page is being captured. It returns true when the capturer count is large then 0.

`contents.incrementCapturerCount([size, stayHidden])`

size Size (optional) - The preferred size for the capturer.
stayHidden Boolean (optional) - Keep the page hidden instead of visible.

Increase the capturer count by one. The page is considered visible when its browser window is hidden and the capturer count is non-zero. If you would like the page to stay hidden, you should ensure that stayHidden is set to true.

This also affects the Page Visibility API.

`contents.decrementCapturerCount([stayHidden])`

stayHidden Boolean (optional) - Keep the page in hidden state instead of visible.

Decrease the capturer count by one. The page will be set to hidden or occluded state when its browser window is hidden or occluded and the capturer count reaches zero. If you want to decrease the hidden capturer count instead you should set stayHidden to true.

`contents.getPrinters()`

获取系统打印机列表

返回 PrinterInfo[]

`contents.print([options], [callback])`

options Object (可选)
- silent Boolean (optional) - Don’t ask user for print settings. 默认值为 false.
- printBackground Boolean (optional) - Prints the background color and image of the web page. 默认值为 false.
- deviceName String (optional) - Set the printer device name to use. Must be the system-defined name and not the ‘friendly’ name, e.g ‘Brother_QL_820NWB’ and not ‘Brother QL-820NWB’.
- color Boolean (optional) - Set whether the printed web page will be in color or grayscale. 默认值为 true。
- margins Object (optional)
  - marginType String (optional) - Can be default, none, printableArea, or custom. If custom is chosen, you will also need to specify top, bottom, left, and right.
  - top Number (optional) - The top margin of the printed web page, in pixels.
  - bottom Number (optional) - The bottom margin of the printed web page, in pixels.
  - left Number (optional) - The left margin of the printed web page, in pixels.
  - right Number (optional) - The right margin of the printed web page, in pixels.
- landscape Boolean (optional) - Whether the web page should be printed in landscape mode. 默认值为 false.
- scaleFactor Number (optional) - The scale factor of the web page.
- pagesPerSheet Number (optional) - The number of pages to print per page sheet.
- collate Boolean (optional) - Whether the web page should be collated.
- copies Number (optional) - The number of copies of the web page to print.
- pageRanges Object[] (optional) - The page range to print. On macOS, only one range is honored.
  - from Number - Index of the first page to print (0-based).
  - to Number - Index of the last page to print (inclusive) (0-based).
- duplexMode String (optional) - Set the duplex mode of the printed web page. Can be simplex, shortEdge, or longEdge.
- dpi Record<string, number> (optional)
  - horizontal Number (optional) - The horizontal dpi.
  - vertical Number (optional) - The vertical dpi.
- header String (optional) - String to be printed as page header.
- footer String (optional) - String to be printed as page footer.
- pageSize String | Size (optional) - Specify page size of the printed document. Can be A3, A4, A5, Legal, Letter, Tabloid or an Object containing height.
callback Function (可选)
- success Boolean - Indicates success of the print call.
- failureReason String - Error description called back if the print fails.

When a custom pageSize is passed, Chromium attempts to validate platform specific minimum values for width_microns and height_microns. Width and height must both be minimum 353 microns but may be higher on some operating systems.

Prints window’s web page. When silent is set to true, Electron will pick the system’s default printer if deviceName is empty and the default settings for printing.

Use page-break-before: always; CSS style to force to print to a new page.

Example usage:

const options = {
  silent: true,
  deviceName: 'My-Printer',
  pageRanges: [{
    from: 0,
    to: 1
  }]
}
win.webContents.print(options, (success, errorType) => {
  if (!success) console.log(errorType)
})

`contents.printToPDF(options)`

选项 对象
- headerFooter Record<string, string> (optional) - the header and footer for the PDF.
  - title String - The title for the PDF header.
  - url String - the url for the PDF footer.
- landscape Boolean (optional) - true for landscape, false for portrait.
- marginsType Integer (optional) - Specifies the type of margins to use. Uses 0 for default margin, 1 for no margin, and 2 for minimum margin.
- scaleFactor Number (optional) - The scale factor of the web page. Can range from 0 to 100.
- pageRanges Record<string, number> (optional) - The page range to print.
  - from Number - Index of the first page to print (0-based).
  - to Number - Index of the last page to print (inclusive) (0-based).
- pageSize String | Size (optional) - Specify page size of the generated PDF. Can be A3, A4, A5, Legal, Letter, Tabloid or an Object containing height and width in microns.
- printBackground Boolean (optional) - Whether to print CSS backgrounds.
- printSelectionOnly Boolean (optional) - Whether to print selection only.

Returns Promise<Buffer> - Resolves with the generated PDF data.

Prints window’s web page as PDF with Chromium’s preview printing custom settings.

The landscape will be ignored if @page CSS at-rule is used in the web page.

By default, an empty options will be regarded as:

{
  marginsType: 0,
  printBackground: false,
  printSelectionOnly: false,
  landscape: false,
  pageSize: 'A4',
  scaleFactor: 100
}

Use page-break-before: always; CSS style to force to print to a new page.

An example of webContents.printToPDF:

const { BrowserWindow } = require('electron')
const fs = require('fs')
const path = require('path')
const os = require('os')
const win = new BrowserWindow({ width: 800, height: 600 })
win.loadURL('http://github.com')
win.webContents.on('did-finish-load', () => {
  // Use default printing options
  win.webContents.printToPDF({}).then(data => {
    const pdfPath = path.join(os.homedir(), 'Desktop', 'temp.pdf')
    fs.writeFile(pdfPath, data, (error) => {
      if (error) throw error
      console.log(`Wrote PDF successfully to ${pdfPath}`)
    })
  }).catch(error => {
    console.log(`Failed to write PDF to ${pdfPath}: `, error)
  })
})

`contents.addWorkSpace(path)`

path String

Adds the specified path to DevTools workspace. Must be used after DevTools creation:

const { BrowserWindow } = require('electron')
const win = new BrowserWindow()
win.webContents.on('devtools-opened', () => {
  win.webContents.addWorkSpace(__dirname)
})

`contents.removeWorkSpace(path)`

path String

Removes the specified path from DevTools workspace.

`contents.setDevToolsWebContents(devToolsWebContents)`

devToolsWebContents WebContents

Uses the devToolsWebContents as the target WebContents to show devtools.

The devToolsWebContents must not have done any navigation, and it should not be used for other purposes after the call.

By default Electron manages the devtools by creating an internal WebContents with native view, which developers have very limited control of. With the setDevToolsWebContents method, developers can use any WebContents to show the devtools in it, including BrowserWindow, BrowserView and <webview> tag.

Note that closing the devtools does not destroy the devToolsWebContents, it is caller’s responsibility to destroy devToolsWebContents.

An example of showing devtools in a <webview> tag:

<html>
<head>
  <style type="text/css">
    * { margin: 0; }
    #browser { height: 70%; }
    #devtools { height: 30%; }
  </style>
</head>
<body>
  <webview id="browser" src="https://github.com"></webview>
  <webview id="devtools" src="about:blank"></webview>
  <script>
    const { ipcRenderer } = require('electron')
    const emittedOnce = (element, eventName) => new Promise(resolve => {
      element.addEventListener(eventName, event => resolve(event), { once: true })
    })
    const browserView = document.getElementById('browser')
    const devtoolsView = document.getElementById('devtools')
    const browserReady = emittedOnce(browserView, 'dom-ready')
    const devtoolsReady = emittedOnce(devtoolsView, 'dom-ready')
    Promise.all([browserReady, devtoolsReady]).then(() => {
      const targetId = browserView.getWebContentsId()
      const devtoolsId = devtoolsView.getWebContentsId()
      ipcRenderer.send('open-devtools', targetId, devtoolsId)
    })
  </script>
</body>
</html>

// Main process
const { ipcMain, webContents } = require('electron')
ipcMain.on('open-devtools', (event, targetContentsId, devtoolsContentsId) => {
  const target = webContents.fromId(targetContentsId)
  const devtools = webContents.fromId(devtoolsContentsId)
  target.setDevToolsWebContents(devtools)
  target.openDevTools()
})

An example of showing devtools in a BrowserWindow:

const { app, BrowserWindow } = require('electron')
let win = null
let devtools = null
app.whenReady().then(() => {
  win = new BrowserWindow()
  devtools = new BrowserWindow()
  win.loadURL('https://github.com')
  win.webContents.setDevToolsWebContents(devtools.webContents)
  win.webContents.openDevTools({ mode: 'detach' })
})

`contents.openDevTools([options])`

options Object (可选)
- mode String - Opens the devtools with specified dock state, can be right, bottom, undocked, detach. Defaults to last used dock state. In undocked mode it’s possible to dock back. In detach mode it’s not.
- activate Boolean (optional) - Whether to bring the opened devtools window to the foreground. 默认值为 true。

Opens the devtools.

When contents is a <webview> tag, the mode would be detach by default, explicitly passing an empty mode can force using last used dock state.

`contents.closeDevTools()`

关闭开发者工具。

`contents.isDevToolsOpened()`

返回Boolean - 开发者工具是否处于开启状态。

`contents.isDevToolsFocused()`

返回Boolean - 开发者工具是否处于当前执行状态。

`contents.toggleDevTools()`

切换开发工具

`contents.inspectElement(x, y)`

x Integer
y Integer

开始检查位于(x, y) 的元素。

`contents.inspectSharedWorker()`

Opens the developer tools for the shared worker context.

`contents.inspectSharedWorkerById(workerId)`

workerId String

Inspects the shared worker based on its ID.

`contents.getAllSharedWorkers()`

Returns SharedWorkerInfo[] - Information about all Shared Workers.

`contents.inspectServiceWorker()`

Opens the developer tools for the service worker context.

`contents.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, just like [postMessage][], so prototype chains will not be included. Sending Functions, Promises, Symbols, WeakMaps, or WeakSets will throw an exception.

NOTE: Sending non-standard JavaScript types such as DOM objects or special Electron objects will throw an exception.

The renderer process can handle the message by listening to channel with the ipcRenderer module.

An example of sending messages from the main process to the renderer process:

// 在主进程中.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
  win = new BrowserWindow({ width: 800, height: 600 })
  win.loadURL(`file://${__dirname}/index.html`)
  win.webContents.on('did-finish-load', () => {
    win.webContents.send('ping', 'whoooooooh!')
  })
})

<!-- index.html -->
<html>
<body>
  <script>
    require('electron').ipcRenderer.on('ping', (event, message) => {
      console.log(message) // Prints 'whoooooooh!'
    })
  </script>
</body>
</html>

`contents.sendToFrame(frameId, channel, ...args)`

frameId Integer | [number, number] - the ID of the frame to send to, or a pair of [processId, frameId] if the frame is in a different process to the main frame.
channel String
...args any[]

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

NOTE: Sending non-standard JavaScript types such as DOM objects or special Electron objects will throw an exception.

The renderer process can handle the message by listening to channel with the ipcRenderer module.

If you want to get the frameId of a given renderer context you should use the webFrame.routingId value. 如下:

// In a renderer process
console.log('My frameId is:', require('electron').webFrame.routingId)

You can also read frameId from all incoming IPC messages in the main process.

// In the main process
ipcMain.on('ping', (event) => {
  console.info('Message came from frameId:', event.frameId)
})

`contents.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.

例如：

// Main process
const { port1, port2 } = new MessageChannelMain()
webContents.postMessage('port', { message: 'hello' }, [port1])
// Renderer process
ipcRenderer.on('port', (e, msg) => {
  const [port] = e.ports
  // ...
})

`contents.enableDeviceEmulation(parameters)`

parameters Object
- screenPosition String - Specify the screen type to emulate (default: desktop):
  - desktop - Desktop screen type.
  - mobile - Mobile screen type.
- screenSize Size - Set the emulated screen size (screenPosition == mobile).
- viewPosition Point - Position the view on the screen (screenPosition == mobile) (default: { x: 0, y: 0 }).
- deviceScaleFactor Integer - Set the device scale factor (if zero defaults to original device scale factor) (default: 0).
- viewSize Size - Set the emulated view size (empty means no override)
- scale Float - Scale of emulated view inside available space (not in fit to view mode) (default: 1).

允许设备模拟给定参数。

`contents.disableDeviceEmulation()`

禁止webContents.enableDeviceEmulation允许的模拟设备

`contents.sendInputEvent(inputEvent)`

inputEvent MouseInputEvent | MouseWheelInputEvent | KeyboardInputEvent

Sends an input event to the page. Note: The BrowserWindow containing the contents needs to be focused for sendInputEvent() to work.

`contents.beginFrameSubscription([onlyDirty ,]callback)`

onlyDirty Boolean (可选) - 默认值为 false.
callback Function
- image NativeImage
- dirtyRect Rectangle

Begin subscribing for presentation events and captured frames, the callback will be called with callback(image, dirtyRect) when there is a presentation event.

The image is an instance of NativeImage that stores the captured frame.

The dirtyRect is an object with x, y, width, height properties that describes which part of the page was repainted. If onlyDirty is set to true, image will only contain the repainted area. onlyDirty defaults to false.

`contents.endFrameSubscription()`

End subscribing for frame presentation events.

`contents.startDrag(item)`

item Object
- file String[] | String - The path(s) to the file(s) being dragged.
- icon NativeImage | String - The image must be non-empty on macOS.

Sets the item as dragging item for current drag-drop operation, file is the absolute path of the file to be dragged, and icon is the image showing under the cursor when dragging.

`contents.savePage(fullPath, saveType)`

fullPath String - The full file path.
saveType String - Specify the save type.
- HTMLOnly - Save only the HTML of the page.
- HTMLComplete - Save complete-html page.
- MHTML - Save complete-html page as MHTML.

Returns Promise<void> - resolves if the page is saved.

const { BrowserWindow } = require('electron')
const win = new BrowserWindow()
win.loadURL('https://github.com')
win.webContents.on('did-finish-load', async () => {
  win.webContents.savePage('/tmp/test.html', 'HTMLComplete').then(() => {
    console.log('Page was saved successfully.')
  }).catch(err => {
    console.log(err)
  })
})

`contents.showDefinitionForSelection()` macOS

Shows pop-up dictionary that searches the selected word on the page.

`contents.isOffscreen()`

Returns Boolean - Indicates whether offscreen rendering is enabled.

`contents.startPainting()`

If offscreen rendering is enabled and not painting, start painting.

`contents.stopPainting()`

If offscreen rendering is enabled and painting, stop painting.

`contents.isPainting()`

Returns Boolean - If offscreen rendering is enabled returns whether it is currently painting.

`contents.setFrameRate(fps)`

fps Integer

If offscreen rendering is enabled sets the frame rate to the specified number. Only values between 1 and 240 are accepted.

`contents.getFrameRate()`

Returns Integer - If offscreen rendering is enabled returns the current frame rate.

`contents.invalidate()`

Schedules a full repaint of the window this web contents is in.

If offscreen rendering is enabled invalidates the frame and generates a new one through the 'paint' event.

`contents.getWebRTCIPHandlingPolicy()`

Returns String - Returns the WebRTC IP Handling Policy.

`contents.setWebRTCIPHandlingPolicy(policy)`

policy String - Specify the WebRTC IP Handling Policy.
- default - Exposes user’s public and local IPs. This is the default behavior. When this policy is used, WebRTC has the right to enumerate all interfaces and bind them to discover public interfaces.
- default_public_interface_only - Exposes user’s public IP, but does not expose user’s local IP. When this policy is used, WebRTC should only use the default route used by http. This doesn’t expose any local addresses.
- default_public_and_private_interfaces - Exposes user’s public and local IPs. When this policy is used, WebRTC should only use the default route used by http. This also exposes the associated default private address. Default route is the route chosen by the OS on a multi-homed endpoint.
- disable_non_proxied_udp - Does not expose public or local IPs. When this policy is used, WebRTC should only use TCP to contact peers or servers unless the proxy server supports UDP.

Setting the WebRTC IP handling policy allows you to control which IPs are exposed via WebRTC. See BrowserLeaks for more details.

`contents.getOSProcessId()`

Returns Integer - The operating system pid of the associated renderer process.

`contents.getProcessId()`

Returns Integer - The Chromium internal pid of the associated renderer. Can be compared to the frameProcessId passed by frame specific navigation events (e.g. did-frame-navigate)

`contents.takeHeapSnapshot(filePath)`

filePath String - Path to the output file.

Returns Promise<void> - Indicates whether the snapshot has been created successfully.

Takes a V8 heap snapshot and saves it to filePath.

`contents.getBackgroundThrottling()`

Returns Boolean - whether or not this WebContents will throttle animations and timers when the page becomes backgrounded. This also affects the Page Visibility API.

`contents.setBackgroundThrottling(allowed)`

allowed Boolean

Controls whether or not this WebContents will throttle animations and timers when the page becomes backgrounded. This also affects the Page Visibility API.

网络控制