In JavaScript, null and undefined both represent "empty" values, but they serve different purposes and are used in specific contexts.
undefined indicates a variable has been declared but not assigned a value, or it refers to a property that doesn’t exist on an object.
null is an explicit assignment to signify an intentional absence of any value, often used to indicate "no value" or "empty" when resetting or clearing an existing value.
Using null and undefined intentionally clarifies the code's purpose and avoids unexpected behavior.