Q
What is the result of the expression typeof undefinedVariable if undefinedVariable is not declared?

Answer & Solution

Answer: Option C
Solution:
When attempting to access a variable that has not been declared, JavaScript returns 'undefined' as the result of the expression 'typeof undefinedVariable'.
Related Questions on Average

What is the difference between 'Undefined' and 'Null' in JavaScript?

A). Undefined is a value, while Null is an absence of value.

B). Undefined is an absence of value, while Null is a value.

C). Undefined is never intentional, while Null is always intentional.

D). Undefined is always intentional, while Null is never intentional.

What does the expression typeof null return in JavaScript?

A). null

B). object

C). undefined

D). function

What is the purpose of using 'Null' over 'Undefined' in certain programming scenarios?

A). To represent an intentional absence of value or object reference.

B). To assign default values to variables.

C). To represent uninitialized variables.

D). To check for variable existence.

Which of the following statements is correct regarding the comparison of 'Undefined' and 'Null'?

A). Undefined and Null are strictly equal in JavaScript.

B). Undefined and Null are not strictly equal in JavaScript.

C). Undefined is considered a subtype of Null.

D). Null is considered a subtype of Undefined.

Which of the following correctly describes the purpose of 'Null' in JavaScript?

A). Null is used to represent an empty array.

B). Null is used to indicate that a variable is uninitialized.

C). Null is used to represent an intentional absence of value.

D). Null is used to check for object properties.

Which of the following is a valid use case for 'Null' in JavaScript?

A). Storing default values in variables.

B). Clearing or resetting object references.

C). Assigning placeholders in arrays.

D). Checking if a variable exists.

Which statement is true regarding the use of 'Undefined'?

A). Undefined is commonly used to reset variables in loops.

B). Undefined is generally avoided and considered a programming error.

C). Undefined is used to represent empty strings.

D). Undefined is only used in function declarations.

Which of the following is an example of using 'Null' in JavaScript?

A). let user = null;

B). let user = undefined;

C). let user;

D). let user = '';

How is 'Null' different from 'Undefined'?

A). Null represents variables that have been initialized but not declared.

B). Null represents an intentional absence of value or object reference.

C). Null is never used in programming.

D). Null is a substitute for 'Undefined'.

Which statement best describes the relationship between 'Undefined' and 'Null' in JavaScript?

A). Undefined and Null are interchangeable and can be used interchangeably in code.

B). Undefined and Null are distinct values representing different states in JavaScript.

C). Undefined is a subset of Null, encompassing all possible values of Null.

D). Null is a subset of Undefined, encompassing all possible values of Undefined.