JavaScript Summary

JavaScript is an essential programming language in web development, often referred to as the brain of web pages.

Let's quickly summarize the key concepts of JavaScript.

1. Variables

Containers for storing data. Types of data include numbers, strings, booleans, objects, and more.

Declare a reassignable variable using let

let userName = 'CodeCompanion';

2. Functions

Reusable blocks of code that perform specific tasks.

Declaration of the greet function

function greet(userName) {
  console.log('Hello, ' + userName + '!');
}

greet('CodeCompanion'); // Outputs: "Hello, CodeCompanion!"

3. Conditional Statements

Execute different code based on certain conditions.

if-else conditional statement

if (userName === 'CodeCompanion') {
  console.log('Hello, CodeCompanion!');
} else {
  console.log('Hello, Guest!');
}

4. Loops

Repeat a block of code multiple times under certain conditions.

for loop

for (let i = 0; i < 5; i++) {
  console.log(i); // Outputs numbers from 0 to 4
}

5. Objects

Collections of data in the form of key-value pairs, where the key is referred to as a property.

person object

const person = {
  name: 'CodeCompanion', // name property, string value
  age: 25, // age property, number value
  greet: function () { // greet property, function value
    console.log('Hello, ' + this.name + '!');
  },
};

person.greet(); // Outputs: "Hello, CodeCompanion!"

6. Events

User interactions with a web page, such as button clicks, form submissions, and page loads.

Detecting a Button Click Event

let button = document.querySelector('button');

// Button click event listener
button.addEventListener('click', function () {
  alert("You've clicked the button!");
});

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