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

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

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Which characters are allowed in JavaScript identifiers?

A). Letters only

B). Letters and numbers only

C). Letters, numbers, $ and _

D). Any special characters

What is the output of the following code: var x = 5, x = 10;

A). Syntax error

B). 5

C). 10

D). Reference error

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 an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

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

A). undefined

B). null

C). 5

D). x

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode