Which is a correct identifier for a variable?

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

Is let a valid identifier in JavaScript?

A). Yes

B). No

C). Only in ES6

D). Only in non-strict mode

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

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

A). Syntax error

B). 5

C). 10

D). Reference error

What will happen if you declare a variable with the name undefined?

A). Syntax error

B). Declares a variable

C). Throws a runtime error

D). Reassigns undefined

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode

Which characters are allowed in JavaScript identifiers?

A). Letters only

B). Letters and numbers only

C). Letters, numbers, $ and _

D). Any special characters

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