Event.returnValue - Web APIs 编辑

The Event property returnValue indicates whether the default action for this event has been prevented or not. It is set to true by default, allowing the default action to occur. Setting this property to false prevents the default action.

Note: While returnValue has been adopted into the DOM standard, it is present primarily to support existing code. You should use preventDefault(), and defaultPrevented instead of this historical property.

Syntax

event.returnValue = bool;

var bool = event.returnValue;

Value

A Boolean value which is true if the event has not been canceled; otherwise, if the event has been canceled or the default has been prevented, the value is false.

The value returned by returnValue is the opposite of the value returned by defaultPrevented.

Usage notes

returnValue was introduced into the DOM by Internet Explorer 6, and due to that browser's ubiquity became so commonly used that other browsers eventually implemented it as well. It has been adopted into the DOM specification, primarily to ensure that existing web content continues to function going forward.

New projects should generally avoid using returnValue, although they may if they choose to do so.

Specifications

Browser compatibility

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