Which of the following is a reserved word in JavaScript?

Which characters are allowed in JavaScript identifiers?

A). Letters only

B). Letters and numbers only

C). Letters, numbers, $ and _

D). Any special characters

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

Which of the following is a valid identifier?

A). if

B). else

C). null

D). value1

What is a valid identifier in JavaScript?

A). 123abc

B). abc123

C). let

D). var

What will be the result of using a reserved word as an identifier?

A). No error

B). Syntax error

C). Logical error

D). Runtime error

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

What will the following code output: var x; x = 5; var y = x;

A). undefined

B). null

C). 5

D). x

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9