Check whether a number is an illegal number:
The result of res will be:
The isNaN() function determines whether a value is an illegal number (Not-a-Number).
This function returns true if the value is NaN, and false if not.
| Function | |||||
|---|---|---|---|---|---|
| isNaN() | Yes | Yes | Yes | Yes | Yes |
| Parameter | Description |
|---|---|
| value | Required. The value to be tested |
| Return Value: | A Boolean. Returns true if the value is NaN, otherwise it returns false |
|---|---|
| JavaScript Version: | 1.0 |
JavaScript Global Functions
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