JavaScript: Introduction
What is JavaScript?
JavaScript is a popular programming language used to make web pages interactive. It runs directly in a web browser and allows users to interact with websites in exciting ways, like clicking buttons, playing videos, or updating content without reloading the page.
Why is JavaScript important?
- It adds life to a website.
- Works with HTML (the structure of a page) and CSS (the design) to make a complete website.
- Without JavaScript, websites would look static and boring.
Key Features of JavaScript:
1. Lightweight: It is simple and does not need heavy software to run.
2. Client-side: Most of the code runs on the user's browser, making websites faster.
3. Interactive: It helps create animations, form validations, image sliders, and more.
4. Cross-platform: Works on all devices and browsers like Chrome, Firefox, Safari, etc.
5. Dynamic: Allows websites to respond to user actions like clicks, scrolls, or typing.
Where is JavaScript used?
- Web Development: To create dynamic websites.
- Game Development: For simple browser games.
- Mobile Apps: Along with frameworks like React Native.
- Server-side Development: Using platforms like Node.js.
In summary, JavaScript is the language that turns a basic webpage into a functional, interactive, and user-friendly experience.
JavaScript: Documents
In JavaScript, documents refer to the web pages you see in a browser. Every webpage is made of HTML, and JavaScript can access and change its content using something called the Document Object Model (DOM).
What is the Document Object Model (DOM)?
- The DOM is like a tree structure of the webpage.
- It represents all the elements (like headings, paragraphs, buttons, etc.) on a webpage.
- JavaScript uses the DOM to interact with and control the content of the webpage.
How JavaScript Works with Documents?
1. Accessing the Elements:
JavaScript can access specific parts of the webpage using methods like:
- `document.getElementById("id")` → Finds an element by its ID.
- `document.querySelector("selector")` → Finds elements by tags or classes.
2. Changing the Content:
JavaScript can change the text or appearance of elements.
Example:
javascript
document.getElementById("heading").innerHTML = "Hello, World!";
This changes the content of an element with the ID `heading`.
3. Responding to User Actions:
JavaScript can detect actions like clicks, typing, or scrolling and react to them.
Example:
javascript
document.getElementById("btn").addEventListener("click", function() {
alert("Button clicked!");
});
4. Adding or Removing Elements:
JavaScript can add new items or delete existing ones dynamically.
Example:
javascript
let newPara = document.createElement("p");
newPara.innerHTML = "This is a new paragraph!";
document.body.appendChild(newPara);
Why Use JavaScript with Documents?
- To make webpages interactive.
- To create dynamic content like animations, forms, and live updates.
- To improve the user experience by responding to actions instantly.
In summary, JavaScript allows us to control and modify documents (webpages) in real-time, making the web much more engaging and responsive.
JavaScript: Forms
In web development, forms are used to collect information from users, like their name, email, or feedback. JavaScript is often used to make forms interactive and to validate the information users enter before it is submitted to the server.
How JavaScript Works with Forms?
1. Accessing Form Elements:
JavaScript can access and control form elements like text boxes, buttons, or dropdowns using their names or IDs.
Example:
javascript
let userName = document.getElementById("username").value;
This code gets the value (text) entered in a text box with the ID `username`.
2. Validating Form Data:
JavaScript checks whether the information entered by the user is correct.
Example:
- Ensure the email has the correct format.
- Check if required fields are not empty.
Example Code:
javascript
function validateForm() {
let email = document.getElementById("email").value;
if (email === "") {
alert("Email is required!");
return false;
}
}
3. Responding to User Input:
JavaScript can give instant feedback to the user.
Example:
- Show a message if the password is too short.
- Highlight errors in the form.
javascript
document.getElementById("password").addEventListener("input", function() {
if (this.value.length < 6) {
document.getElementById("error").innerHTML = "Password must be at least 6 characters long.";
} else {
document.getElementById("error").innerHTML = "";
}
});
4. Submitting the Form:
JavaScript can control what happens when the user submits a form. It can stop the form from being sent if there are errors.
javascript
document.getElementById("myForm").addEventListener("submit", function(event) {
event.preventDefault(); // Stops the form submission
alert("Form submitted successfully!");
});
Why Use JavaScript for Forms?
- Validation: Ensures data is correct before sending it to the server.
- Instant Feedback: Improves user experience by showing errors immediately.
- Customization: Allows forms to do specific tasks like calculating values or enabling/disabling fields.
- Efficiency: Saves time and reduces errors by validating data on the user's browser.
In summary, JavaScript makes forms smarter and more user-friendly by checking, responding to, and controlling the data users enter.
JavaScript: Statements
In JavaScript, statements are the instructions or commands that tell the computer what to do. Each statement performs a specific task, like displaying a message, calculating a number, or making decisions.
What is a JavaScript Statement?
- A statement is like a sentence in a program.
- It ends with a semicolon (;) to show that the instruction is complete.
- JavaScript code is made up of one or more statements.
Example of a JavaScript statement:
javascript
let x = 10; // This is a statement that assigns the value 10 to x.
Types of JavaScript Statements
1. Declaration Statements:
These are used to declare variables or constants.
Example:
javascript
let name = "John"; // Declares a variable 'name' with the value 'John'.
const PI = 3.14; // Declares a constant 'PI' with the value 3.14.
2. Assignment Statements:
Assign a value to a variable.
Example:
javascript
x = 5; // Assigns the value 5 to the variable 'x'.
3. Conditional Statements:
These allow the program to make decisions based on certain conditions.
Example:
javascript
if (x > 0) {
console.log("x is positive");
} else {
console.log("x is not positive");
}
4. Loop Statements:
These are used to repeat actions multiple times.
Example:
javascript
for (let i = 0; i < 5; i++) {
console.log("Number: " + i);
}
5. Function Statements:
These define reusable blocks of code (functions).
Example:
javascript
function greet() {
console.log("Hello!");
}
greet(); // Calls the function to print "Hello!"
6. Output Statements:
These display results or information.
Example:
javascript
console.log("Welcome to JavaScript!"); // Prints to the browser console.
How JavaScript Executes Statements
- JavaScript reads the code line by line (top to bottom).
- Each statement is executed in the order it appears unless there is a condition or a loop.
Key Points to Remember
- Semicolons: End each statement with a semicolon for clarity, although JavaScript can sometimes figure it out on its own.
- Case Sensitivity: JavaScript is case-sensitive, so `let` and `Let` are different.
- Whitespace: Spaces and line breaks are ignored, so you can format the code for readability.
JavaScript: Functions
A function in JavaScript is a reusable block of code that performs a specific task. Instead of writing the same code multiple times, we can put the code inside a function and use it whenever needed.
What is a Function?
- A function is like a recipe: it takes inputs (called parameters), performs some actions, and can give back a result (called a return value).
- Functions help make programs shorter, cleaner, and easier to read.
Why Use Functions?
1. Reusability: Write code once and use it multiple times.
2. Modularity: Break large programs into smaller, manageable parts.
3. Ease of Maintenance: Changes in the function affect all its uses.
4. Clarity: Makes the code more organized and understandable.
How to Write a Function?
1. Function Declaration:
You define a function using the `function` keyword.
javascript
function functionName(parameters) {
// Code to execute
}
2. Calling a Function:
After defining a function, call it by using its name followed by parentheses.
javascript
functionName(arguments);
Example of a Function:
1. Function Without Parameters:
This function does not take any inputs.
javascript
function greet() {
console.log("Hello, World!");
}
greet(); // Outputs: Hello, World!
2. Function With Parameters:
This function takes inputs (parameters) and performs actions with them.
javascript
function addNumbers(a, b) {
return a + b;
}
let result = addNumbers(5, 3); // Outputs: 8
3. Function With Return Value:
This function gives back a result using the `return` statement.
javascript
function square(number) {
return number * number;
}
let sq = square(4); // Outputs: 16
Types of Functions
1. Named Functions:
Functions with a name, as shown in the examples above.
2. Anonymous Functions:
Functions without a name, often used in places like event handlers.
javascript
let greet = function() {
console.log("Hi there!");
};
greet(); // Outputs: Hi there!
3. Arrow Functions (ES6):
A shorter way to write functions.
javascript
let multiply = (x, y) => x * y;
console.log(multiply(3, 4)); // Outputs: 12
Key Points to Remember
- Functions can have no parameters, one parameter, or multiple parameters.
- Use return to send a result back to where the function was called.
- Functions make your code cleaner and more efficient.
In summary, functions are an essential part of JavaScript programming. They allow you to organize your code, avoid repetition, and perform tasks efficiently.
JavaScript: Objects
In JavaScript, an object is a collection of related data and functions stored together. It is used to represent real-world items, like a car, a person, or a book, by bundling their properties (data) and methods (functions).
What is an Object?
- An object is like a container for data and actions.
- Data inside an object is stored as key-value pairs, called properties.
- Functions inside an object are called methods.
Why Use Objects?
1. Organized Data: Store related information together.
2. Real-world Representation: Easily represent complex things like a car or user.
3. Reusability: Use objects to create reusable code.
How to Create an Object?
1. Object Literal: The simplest way to create an object.
javascript
let car = {
brand: "Toyota",
model: "Corolla",
year: 2020,
start: function() {
console.log("The car is starting...");
}
};
- `brand`, `model`, `year` are properties.
- `start` is a method.
2. Accessing Properties and Methods:
- Use the dot operator (`.`) or bracket notation (`[]`) to access values.
Example:
javascript
console.log(car.brand); // Outputs: Toyota
car.start(); // Outputs: The car is starting...
3. Adding or Modifying Properties:
You can add new properties or change existing ones.
javascript
car.color = "red"; // Adds a new property
car.year = 2021; // Updates the year
console.log(car.color); // Outputs: red
Example of an Object:
Let’s represent a person using an object.
javascript
let person = {
name: "John",
age: 25,
greet: function() {
console.log("Hello, my name is " + this.name);
}
};
person.greet(); // Outputs: Hello, my name is John
- `name` and `age` are properties.
- `greet` is a method.
- `this.name` refers to the `name` property of the same object.
Creating Objects Using Constructors
Another way to create objects is by using a constructor function or the `class` keyword.
1. Constructor Function:
javascript
function Person(name, age) {
this.name = name;
this.age = age;
}
let john = new Person("John", 25);
console.log(john.name); // Outputs: John
2. Using Classes (ES6):
javascript
class Animal {
constructor(type) {
this.type = type;
}
speak() {
console.log(this.type + " makes a sound.");
}
}
let dog = new Animal("Dog");
dog.speak(); // Outputs: Dog makes a sound.
Why Are Objects Important?
- Flexibility: Easily store and manage related data.
- Real-world Use Cases: Create models for real-world scenarios like users, cars, or orders.
- Reusability: Once an object or class is defined, it can be used repeatedly.
In summary, JavaScript objects are a powerful way to group data and actions, making your programs more organized and efficient. They help represent real-world items in code and allow you to write reusable and flexible programs.
Introduction to AJAX
AJAX stands for Asynchronous JavaScript and XML. It is a technique used in web development to create faster and more interactive websites by allowing data to be exchanged with a server without refreshing the entire webpage.
What is AJAX?
- Asynchronous: Tasks are performed in the background without stopping other operations.
- JavaScript: The main programming language used for AJAX.
- XML (or JSON): The format used for data exchange (though JSON is more common now).
With AJAX, parts of a webpage can update independently, like loading new comments or live search results, without refreshing the entire page.
Why is AJAX Important?
1. Faster Websites: Only specific parts of the webpage are updated, not the entire page.
2. Improved User Experience: Users don’t see loading screens or page reloads.
3. Real-time Updates: AJAX allows live updates, like chat messages or stock prices.
4. Efficient Data Handling: Reduces the amount of data sent between the server and browser.
How Does AJAX Work?
1. Request:
The browser sends an HTTP request to the server using JavaScript.
2. Server Processing:
The server processes the request and sends back data (usually in JSON or XML format).
3. Response:
The browser receives the data and updates the webpage without reloading it.
Steps in AJAX Communication
1. Create an XMLHttpRequest Object:
This object is used to send requests and receive responses.
javascript
let xhr = new XMLHttpRequest();
2. Open a Request:
Specify the type of request (`GET` or `POST`) and the server URL.
javascript
xhr.open("GET", "data.json", true);
3. Send the Request:
Send the request to the server.
javascript
xhr.send();
4. Handle the Response:
Use the `onreadystatechange` or `onload` event to process the server’s response.
javascript
xhr.onload = function() {
if (xhr.status === 200) {
console.log(xhr.responseText); // Logs the server response
}
};
Example of AJAX in Action
Let’s say a user types in a search box, and suggestions appear without refreshing the page. This happens using AJAX.
Common Use Cases of AJAX
1. Live Search Suggestions: Showing suggestions while typing in a search box.
2. Chat Applications: Sending and receiving messages in real-time.
3. Dynamic Forms: Loading form options (e.g., country and state dropdowns).
4. Real-time Updates: Showing live stock prices, weather updates, etc.
Advantages of AJAX
- Faster and more dynamic web applications.
- Reduces server load and bandwidth usage.
- Improves the user experience by avoiding full-page reloads.
Disadvantages of AJAX
- Requires JavaScript to be enabled on the browser.
- Debugging can be more complex compared to traditional web development.
- May face cross-origin request restrictions.
In summary, AJAX is a powerful technique that makes websites dynamic and responsive by exchanging data with a server in the background without refreshing the entire page. It’s widely used in modern web applications like Google Search, Gmail, and Facebook.
Networking: Internet Addressing
Internet addressing refers to the system of identifying devices (like computers, smartphones, or servers) on a network or the internet so they can communicate with each other. Just like your home has an address to receive letters, every device on the internet has a unique address.
Types of Internet Addresses
1. IP Address (Internet Protocol Address):
- An IP address is a unique number assigned to every device connected to a network.
- It acts as an identifier that allows devices to send and receive information.
Example:
- IPv4: `192.168.1.1` (uses 4 sets of numbers, each ranging from 0-255).
- IPv6: `2001:0db8:85a3:0000:0000:8a2e:0370:7334` (longer and more secure).
2. MAC Address (Media Access Control Address):
- A unique identifier assigned to the hardware of a device (like your computer's Wi-Fi card or phone's network adapter).
- It is specific to your device and doesn't change.
Example: `00:1A:2B:3C:4D:5E`.
3. Domain Name System (DNS):
- Humans find it hard to remember numeric IP addresses. Instead, websites use domain names (like www.google.com).
- DNS translates these domain names into IP addresses so computers can understand them.
Example:
- Domain Name: `www.google.com`.
- IP Address: `142.250.190.14`.
Types of IP Addresses
1. Public IP Address:
- Assigned to your device by your Internet Service Provider (ISP).
- Used to identify your device on the internet.
2. Private IP Address:
- Used within a local network (like your home Wi-Fi).
- Not accessible directly from the internet.
3. Static IP Address:
- A permanent IP address that doesn’t change over time.
4. Dynamic IP Address:
- Assigned temporarily by the network and changes over time.
How Internet Addressing Works
1. When you type a website name (e.g., www.example.com), your computer sends a request to a DNS server.
2. The DNS server translates the domain name into its corresponding IP address (e.g., `192.168.1.1`).
3. Your device uses the IP address to communicate with the web server and display the webpage.
Importance of Internet Addressing
1. Communication: Allows devices to find and communicate with each other.
2. Routing: Helps route data packets to the correct destination on the network.
3. Scalability: Supports billions of devices on the internet.
In summary, internet addressing is a crucial system that helps identify devices on a network, enabling them to exchange information efficiently. It uses IP addresses, MAC addresses, and DNS to make communication simple and reliable.
InetAddress
InetAddress is a concept used to represent IP addresses (either IPv4 or IPv6) in networking. In JavaScript, you don’t directly have an InetAddress class (like in Java), but you can interact with IP addresses through web technologies. You typically deal with IP addresses while working with networking tasks like making HTTP requests, connecting to servers, and using Web APIs.
How InetAddress Works in JavaScript Networking:
In JavaScript, when you interact with web services or perform networking tasks, you often deal with IP addresses, domain names, and DNS (Domain Name System) resolution. While JavaScript doesn’t have a direct `InetAddress` class, you can work with networking tasks using other methods, especially in Node.js, a JavaScript runtime that allows server-side programming.
For example, when making a request to a server, the server will have an IP address that your browser or JavaScript code will connect to, and DNS will help resolve domain names like `www.google.com` to their respective IP addresses.
Example:
To make a request to a server using JavaScript, you don’t manually handle IP addresses; instead, you use URLs (which internally resolve to IP addresses).
javascript
fetch("https://www.example.com")
.then(response => response.text())
.then(data => console.log(data))
.catch(error => console.error("Error:", error));
- When you use `fetch`, JavaScript sends a request to the IP address of `www.example.com` (after resolving the domain name via DNS).
- Internally, the browser or server will use the domain name system (DNS) to resolve the address.
Factory Methods
A Factory Method is a design pattern in programming that provides an interface for creating objects without specifying the exact class of object that will be created. In simpler terms, it’s like a “factory” that makes different types of products (objects) based on the input, without the user needing to know how each product (object) is made.
While factory methods are more commonly discussed in object-oriented programming (like in Java), JavaScript (which is also object-oriented) can also use them to create objects.
How Factory Methods Work in JavaScript:
In JavaScript, a factory method is typically a function that returns an object. It hides the complexity of creating an object and allows you to create objects in a more flexible way.
Example:
Let’s say you want to create different types of vehicles (like a Car and a Bike). Instead of creating them directly, you use a factory method that decides which type of vehicle to create.
javascript
function Vehicle(type) {
if (type === "car") {
return new Car();
} else if (type === "bike") {
return new Bike();
}
}
function Car() {
this.type = "car";
this.drive = function() {
console.log("Driving a car!");
};
}
function Bike() {
this.type = "bike";
this.ride = function() {
console.log("Riding a bike!");
};
}
// Factory Method Example:
let myVehicle = Vehicle("car");
myVehicle.drive(); // Outputs: Driving a car!
In this example:
- The Factory Method is the `Vehicle` function that creates either a `Car` or a `Bike` based on the type passed to it.
- The user doesn’t need to know how to create a `Car` or a `Bike`; they just call the factory method and get the desired object.
Key Concepts:
- InetAddress (in networking) helps identify devices by their IP addresses (either IPv4 or IPv6). In JavaScript, you can interact with it indirectly using domain names and DNS resolution.
- Factory Methods in JavaScript are used to create objects in a flexible and modular way. It allows you to create objects without directly using the `new` keyword, making object creation more organized and easier to manage.
Summary:
- InetAddress: In JavaScript, while you don’t directly use `InetAddress`, networking tasks like resolving domain names and working with IP addresses happen behind the scenes, especially in server-side JavaScript like Node.js.
- Factory Methods: A design pattern used in JavaScript to create objects without directly calling their constructor. It hides the complexity of object creation and allows flexibility in deciding which objects to create based on input.
Instance Methods
- What are Instance Methods?
- Instance methods are functions that belong to an object in object-oriented programming (OOP). When we create an object from a class, instance methods can be used to perform specific actions on that object.
- Example:
- Imagine you have a class Car, and inside it, there’s an instance method called startEngine(). When you create an object (like a specific car), you can use the method startEngine() to start that car’s engine.
- In Networking:
- Instance methods are used to perform actions related to networking. For example, they might handle tasks like opening a connection to the server, sending or receiving data, and closing the connection.
TCP/IP (Transmission Control Protocol/Internet Protocol)
- What is TCP/IP?
- TCP/IP is a set of rules or protocols that determine how data is sent and received over the internet or a network. It's the language that computers use to communicate with each other.
- How does TCP/IP work?
- TCP (Transmission Control Protocol): It breaks data into small packets, ensures that all packets are sent, and reassembles them in the correct order. If any packet is lost, it asks to resend it.
- IP (Internet Protocol): It handles the addressing and routing of data to ensure that it reaches the correct destination computer or device.
- Example:
- Think of TCP/IP as a postal service: TCP is responsible for making sure every letter (data) arrives at the correct destination in the right order, while IP ensures the letter reaches the right address.
- Importance:
- Without TCP/IP, we wouldn't be able to access websites or send emails. It’s the foundation of communication on the internet.
Client Sockets
- What are Client Sockets?
- A socket is an endpoint in a network communication. It is used by a program (client) to send and receive data to and from another program (server) over a network.
- A client socket is used by the client to connect to a server and send or receive data.
- How do Client Sockets work?
- When a client wants to communicate with a server, it creates a socket and tries to connect to the server’s socket using the server’s IP address and a specific port number.
- After the connection is made, the client can send data to the server or receive data from the server.
- Example:
- Think of a client socket as a phone. When you dial a number (connect to a server), the phone (socket) establishes the call (connection). You can now send and receive information through the call (data exchange).
- Use in Networking:
- Web Browsers: When you open a website, your browser creates a client socket to connect to the website’s server.
- Email Clients: When you send or receive emails, your email program uses a client socket to connect to the email server.
In summary:
- Instance Methods are functions used in programming objects.
- TCP/IP is the protocol that ensures data is sent and received properly over the network.
- Client Sockets are used by programs (like browsers or email clients) to communicate with servers over a network.
URL (Uniform Resource Locator) and URL Connection
URL (Uniform Resource Locator)
- What is a URL?
- A URL is a web address used to access resources (like webpages, images, or files) on the internet. It's a string of characters that provides the location of a resource on the web.
- Structure of a URL:
A typical URL looks like this:
`https://www.example.com/index.html`
It has the following parts:
- Protocol: `https://` or `http://` tells your browser how to communicate with the server. It could also be `ftp://` or other protocols.
- Domain Name: `www.example.com` is the address of the server where the resource is stored.
- Path: `/index.html` shows the location of the specific file on the server.
- Example:
- If you type `https://www.google.com` in the browser, the browser looks up the URL and loads the Google homepage.
- How is it used in JavaScript?
- JavaScript can work with URLs to fetch data, navigate between pages, and load resources dynamically without refreshing the page. This is useful in modern websites and web apps.
URL Connection in JavaScript
- What is a URL Connection?
- A URL connection in JavaScript refers to establishing a connection between a client (like a web browser) and a server to access resources or send data. JavaScript uses the URL to connect to a server and fetch data or interact with resources.
- How does it work in JavaScript?
- JavaScript can open a connection to a server using the URL through methods like `fetch()` or XMLHttpRequest. This allows JavaScript to retrieve or send data (like text or images) without reloading the entire page.
- Example: Fetch API
- The `fetch()` method in JavaScript allows you to request data from a URL and then process it when the response is received. It works asynchronously (without blocking other tasks).
- Example code to fetch data from a URL:
javascript
fetch('https://api.example.com/data') // URL to the data source
.then(response => response.json()) // Convert the response to JSON
.then(data => console.log(data)) // Handle the data
.catch(error => console.error('Error:', error)); // Handle errors
- In this example, JavaScript connects to `https://api.example.com/data` to retrieve some data and then processes it.
- Why is URL Connection important?
- URL connections are essential in modern web applications for tasks like:
- Loading new data without refreshing the page (using AJAX).
- Communicating with a server to fetch or send data (like submitting a form).
- Making API calls to third-party services (e.g., fetching weather data or user information).
In summary:
- A URL is a web address that points to a specific resource on the internet.
- URL connection in JavaScript is about connecting to a server using the URL to send or retrieve data asynchronously, allowing web pages to load content dynamically.
TCP/IP Server Sockets and Datagram
TCP/IP Server Sockets
- What is a Server Socket?
- A server socket is a special type of socket used by a server to listen for incoming connections from clients over the network. It helps the server to establish a connection with the client and exchange data.
- How does a Server Socket Work?
- A server creates a socket and binds it to a specific IP address and port number. The server then listens for incoming requests from clients. Once a client connects, the server accepts the connection, and they can start communicating.
- The server and client communicate through the TCP protocol (Transmission Control Protocol), which ensures reliable and ordered delivery of data.
- Steps for a Server to Use a TCP/IP Socket:
1. Create a socket: The server creates a socket and binds it to an address and port.
2. Listen: The server starts listening for client requests.
3. Accept connection: When a client requests to connect, the server accepts the connection.
4. Send/Receive data: The server and client can now send and receive data.
- Example:
- If you're hosting a website, your web server uses a server socket to listen for incoming requests from users' browsers. When someone types your website’s URL, the server accepts the request and sends the website’s content back to the user’s browser.
Datagram
- What is a Datagram?
- A datagram is a basic unit of data used in UDP (User Datagram Protocol) communication. Unlike TCP, which sends data in a reliable and ordered stream, UDP sends data as independent packets called datagrams.
- How Does a Datagram Work?
- When a computer sends a datagram, it doesn’t guarantee delivery, order, or error correction. It's a lightweight, fast method of sending data but lacks reliability.
- Datagrams are typically used for applications where speed is more important than reliability, like streaming videos or real-time games.
- Key Characteristics of a Datagram:
- Unreliable: There's no guarantee the datagram will reach its destination.
- Independent: Each datagram is sent separately and doesn’t rely on others to be received in order.
- No Connection: Unlike TCP, UDP (and datagrams) don’t establish a connection before sending data.
- Example:
- Imagine sending a series of postcards to different addresses. Each postcard (datagram) is sent separately, and you can’t guarantee that all will arrive at their destination, nor can you control the order in which they arrive.
- When to Use Datagrams:
- Datagrams are used in situations where speed is more important than making sure all data is received correctly or in order. Examples include:
- Live video streaming
- Online gaming
- Voice over IP (VoIP)
In summary:
- TCP/IP Server Sockets allow a server to listen for and accept connections from clients over the network, enabling reliable communication.
- A Datagram is a unit of data sent via UDP that is faster but unreliable compared to TCP/IP. It’s often used for applications where speed matters more than reliability.
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