An undefined variable or anything without a value will always return "undefined" in JavaScript. This is not the same as null, despite the fact that both imply an empty state.  You'll typically assign a value to a variable after you declare it, but this is not always the case.

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An undefined variable or anything without a value will always return "undefined" in JavaScript. This is not the same as null, despite the fact that both imply an empty state. In this article, you will learn the various methods and approaches you can use to know if a variable is undefined.

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