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Chukwunonso Joseph Ofodile
Chukwunonso Joseph Ofodile

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JavaScript Basics for Beginners

#javascript #webdev #programming #frontend

JavaScript is one of the most important programming languages in web development. It makes websites interactive and dynamic. While HTML creates the structure and CSS handles the design, JavaScript controls the behavior of a website.

If you want to become a frontend or fullstack developer, learning JavaScript is a must.

1. What is JavaScript?

JavaScript is a programming language used to:

  • Make websites interactive

  • Handle user actions (clicks, typing, scrolling)

  • Update content without refreshing the page

  • Communicate with servers

For example:

  • Showing a popup when a button is clicked

  • Validating a form before submission

  • Creating sliders, dropdowns, and animations

2. Variables

Variables are used to store data.

let name = "John";
const age = 25;
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let can be changed later

const cannot be changed

var older way (not recommended today)

3. Data Types

JavaScript has different types of data:

String = "Hello"

Number = 10, 3.14

Boolean = true or false

Array = ["apple", "banana"]

Object = { name: "John", age: 25 }

let price = 100;
let isOnline = true;
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4. Operators

Arithmetic Operators

  • + (Addition)

  • - (Subtraction)

  • * (Multiplication)

  • / (Division)

  • % (Remainder)

let total = 10 + 5; // 15
Comparison Operators
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Comparison Operators

  • == (Equal)

  • === (Strict Equal)

  • != (Not equal)

  • > (Greater than)

  • < (Less than)

5. Conditional Statements

Conditionals allow your code to make decisions.

let age = 18;

if (age >= 18) {
  console.log("You are an adult");
} else {
  console.log("You are not an adult");
}
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6. Functions

Functions are blocks of code that run when called.

function greet(name) {
  return "Hello " + name;
}

greet("John");
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Functions help you reuse code instead of repeating it.

7. Loops

Loops repeat code multiple times.

For Loop

for (let i = 0; i < 5; i++) {
  console.log(i);
}
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While Loop

let i = 0;

while (i < 5) {
  console.log(i);
  i++;
}
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8. Arrays

Arrays store multiple values in one variable.

let fruits = ["Apple", "Banana", "Orange"];

console.log(fruits[0]); // Apple
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9. Objects

Objects store related data in key-value pairs.

let user = {
  name: "John",
  age: 25,
  isAdmin: false
};

console.log(user.name);
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10. DOM (Document Object Model)

The DOM allows JavaScript to interact with HTML.

Example:

document.getElementById("btn").addEventListener("click", function() {
  alert("Button clicked!");
});
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This makes a button respond when clicked.

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Final Thoughts

JavaScript is the language that brings life to websites. Start with the basics:

  • Variables

  • Data types

  • Operators

  • Conditions

  • Functions

  • Loops

  • Arrays and Objects

Once you master these fundamentals, you can move into advanced topics like APIs, asynchronous JavaScript, frameworks, and backend development with Node.js.

Keep practicing. The more you build, the better you become.

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