Which identifier is valid in strict mode?

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

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

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

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

A). undefined

B). null

C). 5

D). x

Which of the following is a reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number

What does the following code do: var $ = 5;

A). Throws an error

B). Creates a variable named $

C). Creates a variable named var

D). None of the above

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

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode