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
- Available extensions
- Annotations
-
- @JS()
- @staticInterop
Constructors
- BeforeUnloadEvent()
-
factory
Properties
- bubbles → bool
-
Available on Event, provided by the PropsEvent extension
no setter - cancelable → bool
-
Available on Event, provided by the PropsEvent extension
no setter - cancelBubble ↔ bool
-
Available on Event, provided by the PropsEvent extension
getter/setter pair - composed → bool
-
Available on Event, provided by the PropsEvent extension
no setter - currentTarget → EventTarget?
-
Available on Event, provided by the PropsEvent extension
no setter - defaultPrevented → bool
-
Available on Event, provided by the PropsEvent extension
no setter - eventPhase → int
-
Available on Event, provided by the PropsEvent extension
no setter - hashCode → int
-
The hash code for this object.
no setterinherited
- isTrusted → bool
-
Available on Event, provided by the PropsEvent extension
no setter - returnValue ↔ String
-
Available on BeforeUnloadEvent, provided by the PropsBeforeUnloadEvent extension
getter/setter pair - returnValue ↔ dynamic
-
Available on Event, provided by the PropsEvent extension
getter/setter pair - runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- srcElement → EventTarget?
-
Available on Event, provided by the PropsEvent extension
no setter - target → EventTarget?
-
Available on Event, provided by the PropsEvent extension
no setter - timeStamp → double
-
Available on Event, provided by the PropsEvent extension
no setter - type → String
-
Available on Event, provided by the PropsEvent extension
no setter
Methods
-
composedPath(
) → Iterable< EventTarget> -
Available on Event, provided by the PropsEvent extension
-
initEvent(
String type, [bool? bubbles = false, bool? cancelable = false]) → void -
Available on Event, provided by the PropsEvent extension
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
preventDefault(
) → void -
Available on Event, provided by the PropsEvent extension
-
stopImmediatePropagation(
) → void -
Available on Event, provided by the PropsEvent extension
-
stopPropagation(
) → void -
Available on Event, provided by the PropsEvent extension
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited