JavaScript Basic Syntax: Real-Life Examples for Beginners

📚 Quick Study Guide

• 🔑 Variables: Used to store data. Declared using `let`, `const`, or `var`. Example: `let age = 30;`
• 🧮 Data Types: JavaScript has several data types, including:
  • 🔢 Number: Represents numeric values (e.g., 10, 3.14).
  • 📜 String: Represents text (e.g., "Hello, world!").
  • ✅ Boolean: Represents true or false values.
• ➕ Operators: Used to perform operations. Examples: `+` (addition), `-` (subtraction), `*` (multiplication), `/` (division), `=` (assignment).
• 🚦 Conditional Statements: Allow you to execute code based on conditions using `if`, `else if`, and `else`. Example: `if (age >= 18) { console.log("Adult"); }`
• 🔁 Loops: Used to repeat a block of code. Common types include `for` and `while` loops. Example: `for (let i = 0; i < 5; i++) { console.log(i); }`
• 🧩 Functions: Reusable blocks of code. Defined using the `function` keyword. Example: `function greet(name) { console.log("Hello, " + name + "!"); }`

Practice Quiz

1. Which keyword is used to declare a variable in JavaScript?
   1. A. `variable`
   2. B. `let`
   3. C. `string`
   4. D. `data`
2. What is the correct way to write a single-line comment in JavaScript?
   1. A. ``
   2. B. `// This is a comment`
   3. C. `/* This is a comment */`
   4. D. ` This is a comment `
3. Which of the following is NOT a primitive data type in JavaScript?
   1. A. `Number`
   2. B. `String`
   3. C. `Boolean`
   4. D. `Array`
4. What will `console.log(2 + '2');` output in JavaScript?
   1. A. `4`
   2. B. `'4'`
   3. C. `'22'`
   4. D. `Error`
5. Which operator is used for strict equality comparison in JavaScript?
   1. A. `=`
   2. B. `==`
   3. C. `===`
   4. D. `!=`
6. How do you call a function named `myFunction` in JavaScript?
   1. A. `call function myFunction`
   2. B. `myFunction()`
   3. C. `function myFunction()`
   4. D. `call myFunction`
7. What is the purpose of the `if` statement in JavaScript?
   1. A. To declare a variable
   2. B. To repeat a block of code
   3. C. To execute code based on a condition
   4. D. To define a function