`isNaN()` attempts to convert its argument to a number before checking if it's NaN, while `Number.isNaN()` explicitly checks for NaN without conversion, making the latter more accurate and robust in modern JavaScript environments (ECMAScript 6 and above).
JavaScript has two functions to detect NaN values: `isNaN()` and `Number.isNaN()`. While similar, they differ in how they handle non-numeric values. `isNaN()` converts values to numbers before checking if they're NaN, while `Number.isNaN()` strictly checks for existing NaN numbers.
