Which keyword should be used by default to declare variables in modern JavaScript?
A). var
B). let
C). const
D). Either B or C
What will be the output of the following code: var x = 5; var x = 10; console.log(x);
A). 5
B). 10
C). Error
D). undefined
Which keyword allows block-scoped variable declaration?
A). var
B). let
C). const
D). Both B and C
Which keyword is used for declaring variables that should not change?
A). var
B). let
C). const
D). all of the above
What will be the output of the following code: if (true) { let b = 60; } console.log(b);
A). 60
B). undefined
C). Error
D). null
What will be the output of the following code: var e = 110; if (true) { var e = 120; } console.log(e);
A). 110
B). 120
C). Error
D). undefined
What will be the output of the following code: const d = 90; d = 100; console.log(d);
A). 90
B). 100
C). Error
D). undefined
What will be the output of the following code: let c = 70; { let c = 80; console.log(c); } console.log(c);
A). 70 80 80
B). 80 80
C). Error
D). 70 80
What is the scope of a variable declared with 'let' inside a loop?
A). Global
B). Function
C). Loop block
D). Entire script
Can you re-declare a variable using 'const' in the same scope?
A). Yes
B). No
C). Only in functions
D). Only in loops