Which of the following is a reserved word in JavaScript?

What is a valid identifier in JavaScript?

A). 123abc

B). abc123

C). let

D). var

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

Which characters are allowed in JavaScript identifiers?

A). Letters only

B). Letters and numbers only

C). Letters, numbers, $ and _

D). Any special characters

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

Is let a valid identifier in JavaScript?

A). Yes

B). No

C). Only in ES6

D). Only in non-strict mode

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

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

A). undefined

B). null

C). 5

D). x

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6