> NaN !== NaN Why is this listed at all? Mathematically, it makes perfect sense. NaN is what you get when you divide zero by itself: 0/0 gives NaN in the JavaS

> NaN !== NaN Why is this listed at all? Mathematically, it makes perfect sense. NaN is what you get when you divide zero by itself: 0/0 gives NaN in the JavaScript console. Therefore saying that NaN === NaN would amount to saying that 0/0 === 0/0, which is clearly wrong because the left and the right sides could be different numbers (0/0 is undefined). Edit: In the full article, the author acknowledges multiple comments pointing out the above, but then retorts: "But it can still be confusing." This is an incredibly annoying attitude that some software developers have. Math (and life even more so) is complex. Deal with it.