How do you check that a number is NaN in JavaScript?

Question

I’ve only been trying it in Firefox’s JavaScript console, but neither of the following statements return true: ``` parseFloat('geoff') == NaN; parseFloat('geoff') == Number.NaN; ```

Accepted Answer

Try this code:

```
isNaN(parseFloat("geoff"))
```

For checking whether any value is NaN, instead of just numbers, see here: How do you test for NaN in Javascript?

How do you check that a number is NaN in JavaScript?

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