BeforeUnloadEvent class

The beforeunload event is fired when the window, the document and its resources are about to be unloaded. When a non-empty string is assigned to the returnValue Event property, a dialog box appears, asking the users for confirmation to leave the page (see example below). When no value is provided, the event is processed silently. Some implementations only show the dialog box if the frame or any embedded frame receives a user gesture or user interaction. See Browser compatibility for more information.

Event

BeforeUnloadEvent

Bubbles No

Cancelable Yes

Target objects defaultView

Interface Event

Implemented types

• Event

Available extensions

• PropsBeforeUnloadEvent
• PropsEvent

Annotations

• @JS()
• @staticInterop

Constructors

BeforeUnloadEvent()

factory

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited