Detecting the "type" of a DOM object
brendan at mozilla.org
Fri Jun 22 09:41:10 PDT 2012
Allen Wirfs-Brock wrote:
> I agree, I don't see that it presents any technical hurdles.
The DOM is alas built from nominal types, so many people believe (x
instaceof I) for some WebIDL-declared interface I, even if that I came
from another window or frame, "should just work".
Of course, if the other frame's I.prototype has been extended with a
quux property, x won't inherit that property. But that's not how
instanceof is used with DOM interfaces, at least.
At this point I am in favor of making instanceof more useful for WebIDL
consumers, than in being pedantic about prototype chains and multiple
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