Which of the following is an invalid identifier?
A). _variable
B). var$
C). 2variable
D). variable2
Is let a valid identifier in JavaScript?
A). Yes
B). No
C). Only in ES6
D). Only in non-strict mode
What is the maximum length of an identifier?
A). 255 characters
B). 31 characters
C). 64 characters
D). No limit
What is the output of the following code: var x = 5, x = 10;
A). Syntax error
B). 5
C). 10
D). Reference error
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
Which characters are allowed in JavaScript identifiers?
A). Letters only
B). Letters and numbers only
C). Letters, numbers, $ and _
D). Any special characters
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
Which of the following is a valid identifier?
A). if
B). else
C). null
D). value1