JavaScript Exercise

Question 1: What are data types in JavaScript?

In JavaScript, data types define the type of data that can be stored and manipulated by variables. There are primitive data types and non-primitive data types.

Question 2: What are the primitive data types in JavaScript?

The primitive data types in JavaScript are:

Number
String
Boolean
Null
Undefined
Symbol (added in ECMAScript 6)

Question 3: How do you declare a number variable in JavaScript?

In JavaScript, you can declare a number variable using the var, let, or const keywords.

javascript

var num = 10;
let anotherNum = 20;
const PI = 3.14;

Question 4: What is the difference between null and undefined in JavaScript?

null represents the intentional absence of any value, while undefined represents the absence of a value that has not been assigned.

Question 5: How do you declare a string variable in JavaScript?

In JavaScript, you can declare a string variable using single quotes (''), double quotes ("") or backticks (``).

javascript

var str1 = 'Hello';
var str2 = "World";
let str3 = `JavaScript`;

Question 6: What is the boolean data type in JavaScript?

The boolean data type in JavaScript represents a value that is either true or false.

Question 7: How do you declare a boolean variable in JavaScript?

In JavaScript, you can declare a boolean variable by assigning the value true or false to it.

javascript

var isTrue = true;
let isFalse = false;

Question 8: What is the undefined data type in JavaScript?

Undefined in JavaScript represents a variable that has been declared but has not been assigned a value.

Question 9: What is the null data type in JavaScript?

Null in JavaScript represents the intentional absence of any value.

Question 10: What is the typeof operator in JavaScript?

The typeof operator in JavaScript is used to determine the data type of a variable or an expression.