NaN in JavaScript stands for "Not A Number", although its type is actually number. typeof(NaN) // "number". To check if a variable is of value NaN, ... ... <看更多>

NaN 不大於、不小於也不等於任何值，包含NaN 它自己。 isNaN 與 Number.isNaN. 要如何檢測運算結果是否為有效的數字呢？那麼就來檢測是否為 ... ... <看更多>

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Introduction to JavaScript NaN ... JavaScript has the number type that allows you to represent numbers including integer and floating-point numbers. And ... ... <看更多>

To make matters more confusing, undefined is also treated as NaN by Javascript, so when the value can not be converted to a number, it is considered NaN . ... <看更多>

... https://github.com/airbnb/javascript/blob/master/packages/eslint- ... Ok so The isNaN() function determines whether a value is NaN or ... ... <看更多>