event.returnValue = false to replace preventdefault not working in IE 11

Question

The following works fine everywhere except in IE 11:

if( event.keyCode == 18 )
{
    event.preventDefault ? event.preventDefault() : event.returnValue = false 
    altcurrentstate = "keyisdown";
    Xmouse = x; 
    Ymouse= y;
    return false;   
}

I also tried the others ways offered in this site but nope, can't seems to preventDefault in IE 11 no matter what, for the alt and arrow keys. The event.returnValue = false; trick is not working either. Not working with return false either...

Answer 1

尝试在回调函数中实际return false 。

Answer 2

Perhaps you need to make your event cancelable using the initEvent() method.

According to the remarks at the bottom of this page :

If you cannot cancel the event, calling IDOMEvent::preventDefault has no effect.
When you create a custom event by using the IDocumentEvent::createEvent method, you can set the IDOMEvent::cancelable property by using the IDOMEvent::initEvent method.