Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
window.event is a proprietary Microsoft Internet Explorer property which is only available while a DOM event handler is being called. Its value is the Event object currently being handled.
Specifications
Not part of any specification.
Microsoft has a description on MSDN.
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | No support | (Yes) | ? | ? |
| Feature | Android | Edge | Firefox Mobile (Gecko) | IE Phone | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | ? | (Yes) | ? | ? | ? | ? |