Can identifiers start with a digit in JavaScript?
A). Yes
B). No
C). Only in ES5
D). Only in strict mode
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
Can JavaScript identifiers include spaces?
A). Yes
B). No
C). Only in ES6
D). Only in strings
Which of the following is a valid identifier?
A). if
B). else
C). null
D). value1
What will the following code output: var x; x = 5; var y = x;
A). undefined
B). null
C). 5
D). x
What is a valid identifier in JavaScript?
A). 123abc
B). abc123
C). let
D). var
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 an invalid identifier?
A). _variable
B). var$
C). 2variable
D). variable2
Which identifier is valid in strict mode?
A). public
B). _public
C). 123public
D). public$