CaptureController: setFocusBehavior() method

The CaptureController interface's setFocusBehavior() method controls whether the captured tab or window will be focused when an associated MediaDevices.getDisplayMedia() Promise fulfills, or whether the focus will remain with the tab containing the capturing app.

You can set this behavior multiple times before the MediaDevices.getDisplayMedia() call, or once immediately after its Promise resolves. After that, the focus behavior is said to be finalized, and can't be changed.

Syntax

setFocusBehavior(focusBehavior)

Parameters

focusBehavior

An enumerated value that describes whether the user agent should transfer focus to the captured display surface, or keep the capturing app focused. Possible values are focus-captured-surface (transfer focus) and no-focus-change (keep focus on the capturing app).

Return value

None (undefined).

Exceptions

InvalidStateError DOMException

Thrown if:

• The capture stream has been stopped.
• The user chose to share a screen (displaySurface type monitor) rather than a browser tab or window — you can't focus a monitor. In this case the exception is thrown after the MediaDevices.getDisplayMedia() Promise resolves.
• Enough time has elapsed after the MediaDevices.getDisplayMedia() Promise fulfills that the focus behavior has been finalized.

Examples

Basic setFocusBehavior() usage

// Create a new CaptureController instance
const controller = new CaptureController();

// Prompt the user to share a tab, window, or screen.
const stream = await navigator.mediaDevices.getDisplayMedia({ controller });

// Query the displaySurface value of the captured video track
const [track] = stream.getVideoTracks();
const displaySurface = track.getSettings().displaySurface;

if (displaySurface === "browser") {
  // Focus the captured tab.
  controller.setFocusBehavior("focus-captured-surface");
} else if (displaySurface === "window") {
  // Do not move focus to the captured window.
  // Keep the capturing page focused.
  controller.setFocusBehavior("no-focus-change");
}

Specifications

Browser compatibility

See also

• Screen Capture API
• MediaDevices.getDisplayMedia()
• Better screen sharing with Conditional Focus