What will be the output of the following code?
console.log(a); var a = 10;
A). 10
B). undefined
C). Error
D). null
Which of the following is true about variable naming conventions in JavaScript?
A). Variable names can start with a number
B). Variable names are case-insensitive
C). Variable names can include spaces
D). Variable names are case-sensitive
Which keyword should be used to declare a block-scoped variable?
A). var
B). let
C). const
D). Both let and const
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
Which statement is true about variables in JavaScript?
A). They must be declared before use
B). They can only hold numbers
C). They are statically typed
D). They are strongly typed
What will be the output of the following code?
let a = 1; let b = 2; let c = a + b; console.log(c);
A). 12
B). 12
C). 3
D). NaN
Which keyword is used to declare a variable in JavaScript?
A). var
B). let
C). const
D). All of the above
Which of the following is a valid variable name in JavaScript?
A). 2name
B). _name
C). #name
D).
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 will be the output of the following code?
const a = 10; a = 20; console.log(a);
A). 10
B). 20
C). Error
D). undefined