The BeforeInstallPromptEvent is fired at the Window.onbeforeinstallprompt handler before a user is prompted to "install" a web site to a home screen on mobile.

This interface inherits from the Event interface.



Creates a new BeforeInstallPromptEvent.


Inherits properties from its parent, Event.

BeforeInstallPromptEvent.platforms Read only

Returns an array of DOMString items containing the platforms on which the event was dispatched. This is provided for user agents that want to present a choice of versions to the user such as, for example, "web" or "play" which would allow the user to choose between a web version or an Android version.

BeforeInstallPromptEvent.userChoice Read only

Returns a Promise that resolves to a DOMString containing either "accepted" or "dismissed".



Allows a developer to show the install prompt at a time of their own choosing. This method returns a  Promise.


window.addEventListener("beforeinstallprompt", function(e) {
  // log the platforms provided as options in an install prompt
  console.log(e.platforms); // e.g., ["web", "android", "windows"]
  e.userChoice.then(function(choiceResult) {
    console.log(choiceResult.outcome); // either "accepted" or "dismissed"
  }, handleError);

Browser compatibility

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