electron/docs/api/browser-window.md

BrowserWindow

The BrowserWindow class gives you the ability to create a browser window. For example:

const BrowserWindow = require('electron').BrowserWindow;

var win = new BrowserWindow({ width: 800, height: 600, show: false });
win.on('closed', function() {
  win = null;
});

win.loadURL('https://github.com');
win.show();

You can also create a window without chrome by using Frameless Window API.

Class: BrowserWindow

BrowserWindow is an EventEmitter.

It creates a new BrowserWindow with native properties as set by the options.

new BrowserWindow([options])

options Object (optional), properties:

• width Integer - Window's width. Default is 800 pixels.
• height Integer - Window's height. Default is 600 pixels.
• x Integer - Window's left offset from screen.
• y Integer - Window's top offset from screen.
• useContentSize Boolean - The width and height would be used as web page's size, which means the actual window's size will include window frame's size and be slightly larger. Default is false.
• center Boolean - Show window in the center of the screen.
• minWidth Integer - Window's minimum width.
• minHeight Integer - Window's minimum height.
• maxWidth Integer - Window's maximum width.
• maxHeight Integer - Window's maximum height.
• resizable Boolean - Whether window is resizable.
• alwaysOnTop Boolean - Whether the window should always stay on top of other windows.
• fullscreen Boolean - Whether the window should show in fullscreen. When set to false the fullscreen button will be hidden or disabled on OS X.
• skipTaskbar Boolean - Whether to show the window in taskbar.
• kiosk Boolean - The kiosk mode.
• title String - Default window title.
• icon NativeImage - The window icon, when omitted on Windows the executable's icon would be used as window icon.
• show Boolean - Whether window should be shown when created. Default is true.
• frame Boolean - Specify false to create a Frameless Window.
• acceptFirstMouse Boolean - Whether the web view accepts a single mouse-down event that simultaneously activates the window.
• disableAutoHideCursor Boolean - Whether to hide cursor when typing.
• autoHideMenuBar Boolean - Auto hide the menu bar unless the Alt key is pressed.
• enableLargerThanScreen Boolean - Enable the window to be resized larger than screen.
• backgroundColor String - Window's background color as Hexadecimal value, like #66CD00 or #FFF. This is only implemented on Linux and Windows.
• darkTheme Boolean - Forces using dark theme for the window, only works on some GTK+3 desktop environments.
• transparent Boolean - Makes the window transparent.
• type String - Specifies the type of the window, which applies additional platform-specific properties.
  • On Linux, possible types are desktop, dock, toolbar, splash, notification.
  • On OS X, possible types are desktop, textured. The textured type adds metal gradient appearance (NSTexturedBackgroundWindowMask). The desktop type places the window at the desktop background window level (kCGDesktopWindowLevel - 1). Note that desktop window will not receive focus, keyboard or mouse events, but you can use globalShortcut to receive input sparingly.
• titleBarStyle String, OS X - specifies the style of window title bar. This option is supported on OS X 10.10 Yosemite and newer. There are three possible values:
  • default or not specified results in the standard gray opaque Mac title bar.
  • hidden results in a hidden title bar and a full size content window, yet the title bar still has the standard window controls ("traffic lights") in the top left.
  • hidden-inset results in a hidden title bar with an alternative look where the traffic light buttons are slightly more inset from the window edge.
• webPreferences Object - Settings of web page's features, properties:

  • nodeIntegration Boolean - Whether node integration is enabled. Default is true.

  • preload String - Specifies a script that will be loaded before other scripts run in the page. This script will always have access to node APIs no matter whether node integration is turned on or off. The value should be the absolute file path to the script.

    When node integration is turned off, the preload script can reintroduce Node global symbols back to the global scope. See example here.

  • partition String - Sets the session used by the page. If partition starts with persist:, the page will use a persistent session available to all pages in the app with the same partition. if there is no persist: prefix, the page will use an in-memory session. By assigning the same partition, multiple pages can share the same session. If the partition is unset then default session of the app will be used.

  • zoomFactor Number - The default zoom factor of the page, 3.0 represents 300%.

  • javascript Boolean

  • webSecurity Boolean - When setting false, it will disable the same-origin policy (Usually using testing websites by people), and set allowDisplayingInsecureContent and allowRunningInsecureContent to true if these two options are not set by user.

  • allowDisplayingInsecureContent Boolean - Allow an https page to display content like images from http URLs.

  • allowRunningInsecureContent Boolean - Allow a https page to run JavaScript, CSS or plugins from http URLs.

  • images Boolean

  • java Boolean

  • textAreasAreResizable Boolean

  • webgl Boolean

  • webaudio Boolean

  • plugins Boolean - Whether plugins should be enabled.

  • experimentalFeatures Boolean

  • experimentalCanvasFeatures Boolean

  • overlayScrollbars Boolean

  • overlayFullscreenVideo Boolean

  • sharedWorker Boolean

  • directWrite Boolean - Whether the DirectWrite font rendering system on Windows is enabled.

  • pageVisibility Boolean - Page would be forced to be always in visible or hidden state once set, instead of reflecting current window's visibility. Users can set it to true to prevent throttling of DOM timers.

Events

The BrowserWindow object emits the following events:

Note: Some events are only available on specific operating systems and are labeled as such.

Event: 'page-title-updated'

Returns:

• event Event

Emitted when the document changed its title, calling event.preventDefault() would prevent the native window's title to change.

Event: 'close'

Returns:

• event Event

Emitted when the window is going to be closed. It's emitted before the beforeunload and unload event of the DOM. Calling event.preventDefault() will cancel the close.

Usually you would want to use the beforeunload handler to decide whether the window should be closed, which will also be called when the window is reloaded. In Electron, returning an empty string or false would cancel the close. For example:

window.onbeforeunload = function(e) {
  console.log('I do not want to be closed');

  // Unlike usual browsers, in which a string should be returned and the user is
  // prompted to confirm the page unload, Electron gives developers more options.
  // Returning empty string or false would prevent the unloading now.
  // You can also use the dialog API to let the user confirm closing the application.
  e.returnValue = false;
};

Event: 'closed'

Emitted when the window is closed. After you have received this event you should remove the reference to the window and avoid using it anymore.

Event: 'unresponsive'

Emitted when the web page becomes unresponsive.

Event: 'responsive'

Emitted when the unresponsive web page becomes responsive again.

Event: 'blur'

Emitted when the window loses focus.

Event: 'focus'

Emitted when the window gains focus.

Event: 'maximize'

Emitted when window is maximized.

Event: 'unmaximize'

Emitted when the window exits from maximized state.

Event: 'minimize'

Emitted when the window is minimized.

Event: 'restore'

Emitted when the window is restored from minimized state.

Event: 'resize'

Emitted when the window is getting resized.

Event: 'move'

Emitted when the window is getting moved to a new position.

Note: On OS X this event is just an alias of moved.

Event: 'moved' OS X

Emitted once when the window is moved to a new position.

Event: 'enter-full-screen'

Emitted when the window enters full screen state.

Event: 'leave-full-screen'

Emitted when the window leaves full screen state.

Event: 'enter-html-full-screen'

Emitted when the window enters full screen state triggered by html api.

Event: 'leave-html-full-screen'

Emitted when the window leaves full screen state triggered by html api.

Event: 'app-command' Windows

Emitted when an App Command is invoked. These are typically related to keyboard media keys or browser commands, as well as the "Back" button built into some mice on Windows.

someWindow.on('app-command', function(e, cmd) {
  // Navigate the window back when the user hits their mouse back button
  if (cmd === 'browser-backward' && someWindow.webContents.canGoBack()) {
    someWindow.webContents.goBack();
  }
});

Methods

The BrowserWindow object has the following methods:

BrowserWindow.getAllWindows()

Returns an array of all opened browser windows.

BrowserWindow.getFocusedWindow()

Returns the window that is focused in this application.

BrowserWindow.fromWebContents(webContents)

• webContents WebContents

Find a window according to the webContents it owns.

BrowserWindow.fromId(id)

• id Integer

Find a window according to its ID.

BrowserWindow.addDevToolsExtension(path)

• path String

Adds DevTools extension located at path, and returns extension's name.

The extension will be remembered so you only need to call this API once, this API is not for programming use.

BrowserWindow.removeDevToolsExtension(name)

• name String

Remove the DevTools extension whose name is name.

Instance Properties

Objects created with new BrowserWindow have the following properties:

// In this example `win` is our instance
var win = new BrowserWindow({ width: 800, height: 600 });

win.webContents

The WebContents object this window owns, all web page related events and operations will be done via it.

See the webContents documentation for its methods and events.

win.id

The unique ID of this window.

Instance Methods

Objects created with new BrowserWindow have the following instance methods:

Note: Some methods are only available on specific operating systems and are labeled as such.

win.destroy()

Force closing the window, the unload and beforeunload event won't be emitted for the web page, and close event will also not be emitted for this window, but it guarantees the closed event will be emitted.

You should only use this method when the renderer process (web page) has crashed.

win.close()

Try to close the window, this has the same effect with user manually clicking the close button of the window. The web page may cancel the close though, see the close event.

win.focus()

Focus on the window.

win.isFocused()

Returns a boolean, whether the window is focused.

win.show()

Shows and gives focus to the window.

win.showInactive()

Shows the window but doesn't focus on it.

win.hide()

Hides the window.

win.isVisible()

Returns a boolean, whether the window is visible to the user.

win.maximize()

Maximizes the window.

win.unmaximize()

Unmaximizes the window.

win.isMaximized()

Returns a boolean, whether the window is maximized.

win.minimize()

Minimizes the window. On some platforms the minimized window will be shown in the Dock.

win.restore()

Restores the window from minimized state to its previous state.

win.isMinimized()

Returns a boolean, whether the window is minimized.

win.setFullScreen(flag)

• flag Boolean

Sets whether the window should be in fullscreen mode.

win.isFullScreen()

Returns a boolean, whether the window is in fullscreen mode.

win.setAspectRatio(aspectRatio[, extraSize]) OS X

• aspectRatio The aspect ratio we want to maintain for some portion of the content view.
• extraSize Object (optional) - The extra size not to be included while maintaining the aspect ratio. Properties:
  • width Integer
  • height Integer

This will have a window maintain an aspect ratio. The extra size allows a developer to have space, specified in pixels, not included within the aspect ratio calculations. This API already takes into account the difference between a window's size and its content size.

Consider a normal window with an HD video player and associated controls. Perhaps there are 15 pixels of controls on the left edge, 25 pixels of controls on the right edge and 50 pixels of controls below the player. In order to maintain a 16:9 aspect ratio (standard aspect ratio for HD @1920x1080) within the player itself we would call this function with arguments of 16/9 and [ 40, 50 ]. The second argument doesn't care where the extra width and height are within the content view--only that they exist. Just sum any extra width and height areas you have within the overall content view.

win.setBounds(options)

options Object, properties:

• x Integer
• y Integer
• width Integer
• height Integer

Resizes and moves the window to width, height, x, y.

win.getBounds()

Returns an object that contains window's width, height, x and y values.

win.setSize(width, height)

• width Integer
• height Integer

Resizes the window to width and height.

win.getSize()

Returns an array that contains window's width and height.

win.setContentSize(width, height)

• width Integer
• height Integer

Resizes the window's client area (e.g. the web page) to width and height.

win.getContentSize()

Returns an array that contains window's client area's width and height.

win.setMinimumSize(width, height)

• width Integer
• height Integer

Sets the minimum size of window to width and height.

win.getMinimumSize()

Returns an array that contains window's minimum width and height.

win.setMaximumSize(width, height)

• width Integer
• height Integer

Sets the maximum size of window to width and height.

win.getMaximumSize()

Returns an array that contains window's maximum width and height.

win.setResizable(resizable)

• resizable Boolean

Sets whether the window can be manually resized by user.

win.isResizable()

Returns whether the window can be manually resized by user.

win.setAlwaysOnTop(flag)

• flag Boolean

Sets whether the window should show always on top of other windows. After setting this, the window is still a normal window, not a toolbox window which can not be focused on.

win.isAlwaysOnTop()

Returns whether the window is always on top of other windows.

win.center()

Moves window to the center of the screen.

win.setPosition(x, y)

• x Integer
• y Integer

Moves window to x and y.

win.getPosition()

Returns an array that contains window's current position.

win.setTitle(title)

• title String

Changes the title of native window to title.

win.getTitle()

Returns the title of the native window.

Note: The title of web page can be different from the title of the native window.

win.flashFrame(flag)

• flag Boolean

Starts or stops flashing the window to attract user's attention.

win.setSkipTaskbar(skip)

• skip Boolean

Makes the window not show in the taskbar.

win.setKiosk(flag)

• flag Boolean

Enters or leaves the kiosk mode.

win.isKiosk()

Returns whether the window is in kiosk mode.

win.hookWindowMessage(message, callback) Windows

• message Integer
• callback Function

Hooks a windows message. The callback is called when the message is received in the WndProc.

win.isWindowMessageHooked(message) Windows

• message Integer

Returns true or false depending on whether the message is hooked.

win.unhookWindowMessage(message) Windows

• message Integer

Unhook the window message.

win.unhookAllWindowMessages() Windows

Unhooks all of the window messages.

win.setRepresentedFilename(filename) OS X

• filename String

Sets the pathname of the file the window represents, and the icon of the file will show in window's title bar.

win.getRepresentedFilename() OS X

Returns the pathname of the file the window represents.

win.setDocumentEdited(edited) OS X

• edited Boolean

Specifies whether the window’s document has been edited, and the icon in title bar will become grey when set to true.

win.isDocumentEdited() OS X

Whether the window's document has been edited.

win.focusOnWebView()

win.blurWebView()

win.capturePage([rect, ]callback)

• rect Object (optional)- The area of page to be captured, properties:
  • x Integer
  • y Integer
  • width Integer
  • height Integer
• callback Function

Captures a snapshot of the page within rect. Upon completion callback will be called with callback(image). The image is an instance of NativeImage that stores data of the snapshot. Omitting rect will capture the whole visible page.

win.print([options])

Same as webContents.print([options])

win.printToPDF(options, callback)

Same as webContents.printToPDF(options, callback)

win.loadURL(url[, options])

Same as webContents.loadURL(url[, options]).

win.reload()

Same as webContents.reload.

win.setMenu(menu) Linux Windows

• menu Menu

Sets the menu as the window's menu bar, setting it to null will remove the menu bar.

win.setProgressBar(progress)

• progress Double

Sets progress value in progress bar. Valid range is [0, 1.0].

Remove progress bar when progress < 0; Change to indeterminate mode when progress > 1.

On Linux platform, only supports Unity desktop environment, you need to specify the *.desktop file name to desktopName field in package.json. By default, it will assume app.getName().desktop.

win.setOverlayIcon(overlay, description) Windows 7+

• overlay NativeImage - the icon to display on the bottom right corner of the taskbar icon. If this parameter is null, the overlay is cleared
• description String - a description that will be provided to Accessibility screen readers

Sets a 16px overlay onto the current taskbar icon, usually used to convey some sort of application status or to passively notify the user.

win.setThumbarButtons(buttons) Windows 7+

buttons Array of button Objects:

button Object, properties:

• icon NativeImage - The icon showing in thumbnail toolbar.
• tooltip String (optional) - The text of the button's tooltip.
• flags Array (optional) - Control specific states and behaviors of the button. By default, it uses enabled. It can include following Strings:
  • enabled - The button is active and available to the user.
  • disabled - The button is disabled. It is present, but has a visual state indicating it will not respond to user action.
  • dismissonclick - When the button is clicked, the taskbar button's flyout closes immediately.
  • nobackground - Do not draw a button border, use only the image.
  • hidden - The button is not shown to the user.
  • noninteractive - The button is enabled but not interactive; no pressed button state is drawn. This value is intended for instances where the button is used in a notification.
• click - Function

Add a thumbnail toolbar with a specified set of buttons to the thumbnail image of a window in a taskbar button layout. Returns a Boolean object indicates whether the thumbnail has been added successfully.

The number of buttons in thumbnail toolbar should be no greater than 7 due to the limited room. Once you setup the thumbnail toolbar, the toolbar cannot be removed due to the platform's limitation. But you can call the API with an empty array to clean the buttons.

win.showDefinitionForSelection() OS X

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

win.setAutoHideMenuBar(hide)

• hide Boolean

Sets whether the window menu bar should hide itself automatically. Once set the menu bar will only show when users press the single Alt key.

If the menu bar is already visible, calling setAutoHideMenuBar(true) won't hide it immediately.

win.isMenuBarAutoHide()

Returns whether menu bar automatically hides itself.

win.setMenuBarVisibility(visible)

• visible Boolean

Sets whether the menu bar should be visible. If the menu bar is auto-hide, users can still bring up the menu bar by pressing the single Alt key.

win.isMenuBarVisible()

Returns whether the menu bar is visible.

win.setVisibleOnAllWorkspaces(visible)

• visible Boolean

Sets whether the window should be visible on all workspaces.

Note: This API does nothing on Windows.

win.isVisibleOnAllWorkspaces()

Returns whether the window is visible on all workspaces.

Note: This API always returns false on Windows.