Q114
If we have an object r and want to know if it is a Range object, we can write:
A.
r typeof Range
B.
r is Range
C.
r equals Range
D.
r instanceof Range
AnswerAnswer: Option D
Solution
Answer: Option D
Solution:
The r instanceof Range returns true if r inherits from Range.prototype. The instanceof operatory does not actually check whether r was initialized by the Range constructor.