Which of the following is a valid identifier?

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

A). Syntax error

B). 5

C). 10

D). Reference error

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

Which of these is an invalid identifier?

A). foo_bar

B). fooBar

C). foo-bar

D). foo$bar

Is let a valid identifier in JavaScript?

A). Yes

B). No

C). Only in ES6

D). Only in non-strict mode

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

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