The 4th element in the array is undefined. Out of bound array elements are undefined.Ĭonsole.log('The 4th element in the array is ',array1) Formal parameters of a function without actual arguments.Ĭonsole.log('The value of arg1 is ',arg1)

$javascript undefined$

To formal arguments of a function without actual arguments.The return value of the function is undefined. A return without an explicit value.Ĭonsole.log('The return value of the function is ',undefinedRet()) To a return value of a function that’s not explicitly defined.The value of non-existent property 'name' is undefined.

A non-existent property in an object.Ĭonsole.log('The value of non-existent property 'name' is ', undefinedObj.name)

To a non-existent property of an object.

The programmer declares the variable without initializing it to any value (not even null).

A variable declared without a value assigned.Ĭonsole.log('The value of undefinedVar is ',undefinedVar)

To a declared but uninitialized variable.

Some of the situations where JavaScript assigns the value undefined are: Undefined is a primitive value automatically assigned by JavaScript to indicate the unintentional absence of any object value.

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An object can be emptied by setting it to null. The setting of the value must be done manually by the user as JavaScript never sets the value as null. When it gets assigned to a variable, it represents no value. It is to show that the variable has no value. When we assign null as a value to any variable, it means that it is empty or blank. The variable which has been assigned as null contains no value. Null is basically an assignment value given to a variable. The same meaning is analogous to the meaning of null in programming. We have heard the word ' null' many times in English.

Various examples of null and undefined in JavaScript will be covered.

This article deals with the meaning and the difference between null and undefined in JavaScript.

Undefined, on the other hand, means the variable has been declared, but its value has not been assigned. Null in JavaScript means an empty value and is also a primitive type in JavaScript.

Javascript undefined