This isn't IEEE 754 floating point, but rather Javascript floats. For example, it gets (n!=0)/0 wrong by using the javascript NaN value instead of the IEEE 754 value of +-Infinity. For a playground like this, I think that it would be interesting to show how IEEE 754 and Javascript differ -- division by zero, the max function, etc.<p>Edit: I had misremembered one of the differences. Javascript does get division by zero correct. The biggest differences are in the comparisons, Javascript propagates NaNs more frequently.
Lack of understanding of floating point numbers is one of the most persistent and pervasive problems in programming. Just look at Stack Overflow on any given day. I've also helped co-workers more times than I can count on problems that stem from not understanding how floats work.
If someone doesn't know what IEEE 754 is - it's "a technical standard for floating-point computation" <a href="https://en.wikipedia.org/wiki/IEEE_floating_point" rel="nofollow">https://en.wikipedia.org/wiki/IEEE_floating_point</a>