What is a valid identifier in JavaScript?

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode

Which of these is an invalid identifier?

A). foo_bar

B). fooBar

C). foo-bar

D). foo$bar

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

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

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

A). Syntax error

B). 5

C). 10

D). Reference error

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 maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9