Which of the following is an invalid identifier?
A). _variable
B). var$
C). 2variable
D). variable2
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
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 output of the following code: var x = 5, x = 10;
A). Syntax error
B). 5
C). 10
D). Reference error
What does the following code do: var $ = 5;
A). Throws an error
B). Creates a variable named $
C). Creates a variable named var
D). None of the above
Can an identifier be a single character?
A). Yes
B). No
C). Only in ES5
D). Only in ES6
Are JavaScript identifiers case-sensitive?
A). Yes
B). No
C). Only in ES6
D). Only in strict mode
What will the following code output: var x; x = 5; var y = x;
A). undefined
B). null
C). 5
D). x
Can identifiers start with a digit in JavaScript?
A). Yes
B). No
C). Only in ES5
D). Only in strict mode