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
What will the following code output: var x; x = 5; var y = x;
A). undefined
B). null
C). 5
D). x
Which of these is an invalid identifier?
A). foo_bar
B). fooBar
C). foo-bar
D). foo$bar
Which of the following is a valid identifier name?
A). var
B). 123abc
C). _123abc
D). #abc123
Is let a valid identifier in JavaScript?
A). Yes
B). No
C). Only in ES6
D). Only in non-strict mode
What is a valid identifier in JavaScript?
A). 123abc
B). abc123
C). let
D). var
Can an identifier be a single character?
A). Yes
B). No
C). Only in ES5
D). Only in ES6
What will happen if you declare a variable with the name undefined?
A). Syntax error
B). Declares a variable
C). Throws a runtime error
D). Reassigns undefined
Which of the following is an invalid identifier?
A). _variable
B). var$
C). 2variable
D). variable2
Are JavaScript identifiers case-sensitive?
A). Yes
B). No
C). Only in ES6
D). Only in strict mode