Which of the following scenarios is a common cause of variables having an 'Undefined' value?
A). When variables are explicitly set to 'Undefined'.
B). When variables are declared but not initialized.
C). When variables are intentionally set to 'Null'.
D). When variables are assigned default values.
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.
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.
How do you check if a variable has an 'Undefined' value in JavaScript?
A). Using the undefined keyword.
B). Using the null keyword.
C). Using the typeof operator.
D). Using the empty keyword.
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.
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.
What is the result of the expression typeof undefinedVariable if undefinedVariable is not declared?
A). object
B). function
C). undefined
D). null
When does a variable typically have an 'Undefined' value?
A). When it is intentionally set to represent no value.
B). When it is assigned a default value.
C). When it is declared but not initialized.
D). When it is explicitly set to 'Undefined'.
How does the typeof operator behave when applied to an 'Undefined' value?
A). It returns 'undefined'.
B). It returns 'null'.
C). It throws an error.
D). It returns 'object'.
What does the expression null == undefined return in JavaScript?
A). 1
B). 0
C). undefined
D). null