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

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

Which of the following is a reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

What will be the result of using a reserved word as an identifier?

A). No error

B). Syntax error

C). Logical error

D). Runtime error

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9

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

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

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 these is an invalid identifier?

A). foo_bar

B). fooBar

C). foo-bar

D). foo$bar