Can an identifier be a single character?

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

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

What is a valid identifier in JavaScript?

A). 123abc

B). abc123

C). let

D). var

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

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

A). undefined

B). null

C). 5

D). x

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

Which of the following is a reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number