Event.returnValue

已弃用: 不再推荐使用该特性。虽然一些浏览器仍然支持它，但也许已从相关的 web 标准中移除，也许正准备移除或出于兼容性而保留。请尽量不要使用该特性，并更新现有的代码；参见本页面底部的兼容性表格以指导你作出决定。请注意，该特性随时可能无法正常工作。

Event.returnValue 属性表示该事件的默认操作是否已被阻止。默认情况下，它被设置为 true，即允许进行默认操作。将该属性设置为 false 即可阻止默认操作。

备注： 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.

语法

event.returnValue = bool;

var bool = event.returnValue;

值

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.

使用说明

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.

规范

Specification
DOM Standard # dom-event-returnvalue

浏览器兼容性

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