Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
You should avoid using this property in new code, and should instead use the
Event passed into the event handler function. This property is not universally supported and even when supported introduces potential fragility to your code.
Note: This property can be fragile, in that there may be situations in which the returned
Event is not the expected value. In addition,
Window.event is not accurate for events dispatched within shadow trees.
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