What is the difference between undefined and null in JavaScript?

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Sana

I am online Quran teacher 7 years

undefined means a variable has been declared but has not yet been assigned a value, whereas null is an assignment value, meaning that a variable has been declared and given the value of null .
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Experienced Full Stack Developer and Instructor.

undefined: It is a type in JavaScript.Indicates the absence of a value or that a variable has been declared but not assigned a value. null: It is an object (due to a historical bug in JavaScript).Represents the intentional absence of any object value, used explicitly to denote "nothing" or "empty." ...
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undefined: It is a type in JavaScript.Indicates the absence of a value or that a variable has been declared but not assigned a value. null: It is an object (due to a historical bug in JavaScript).Represents the intentional absence of any object value, used explicitly to denote "nothing" or "empty." read less
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