A.["A","B","C","D","X","Y"] B.["Y""A","B","C","D","X"] C.["X","A","B","C","D","Y"] D.["X","Y""A","B","C","D"]
A.undefined B.報(bào)錯(cuò) C.10 D.5
A.NaN是一個(gè)數(shù) B.NaN是number的特殊類型 C.NaN和任何值都不相等 D.NaN只和自己相等