Which of the following will cause an error?
A). let a = 10; a = 20;
B). const a = 10; a = 20;
C). var a = 10; a = 20;
D). None of the above
What is hoisting in JavaScript?
A). Function call before declaration
B). Variable declared at the top
C). Variable and function declaration are moved to the top
D). Variable scope
What is the correct syntax for declaring a variable in JavaScript?
A). let myVar = 5;
B). myVar let = 5;
C). 5 = let myVar;
D). let = myVar 5;
What will be the output of the following code?
var x = 5; var y = 6; var z = x + y;
A). 11
B). 11
C). 5
D). 6
What is the difference between let and var?
A). let is function-scoped, var is block-scoped
B). let is block-scoped, var is function-scoped
C). Both are block-scoped
D). Both are function-scoped
What will be the output of the following code?
let x; console.log(x);
A). null
B). undefined
C). 0
D). NaN
Which of the following is true about 'const' variables in JavaScript?
A). They can be redeclared
B). They cannot be reassigned
C). They can be reassigned
D). They are always undefined
What will be the output of the following code?
console.log(a); var a = 10;
A). 10
B). undefined
C). Error
D). null
What will be the output of the following code?
const a = 10; a = 20; console.log(a);
A). 10
B). 20
C). Error
D). undefined
Which keyword should be used to declare a block-scoped variable?
A). var
B). let
C). const
D). Both let and const