Web Development - HTML, CSS & JavaScript
Learn to code and become a Web Developer with HTML, CSS, JavaScript , Reactjs, Wordpress, PHP, Mern & Nodejs knowledge Managed by: @love_data
Mostrar más📈 Análisis del canal de Telegram Web Development - HTML, CSS & JavaScript
El canal Web Development - HTML, CSS & JavaScript (@javascript_courses) en el segmento lingüístico de Inglés es un actor destacado. Actualmente la comunidad reúne a 55 670 suscriptores, ocupando la posición 2 369 en la categoría Tecnologías y Aplicaciones y el puesto 6 195 en la región India.
📊 Métricas de audiencia y dinámica
Desde su creación el невідомо, el proyecto ha mostrado un crecimiento acelerado, reuniendo a 55 670 suscriptores.
Según los últimos datos del 25 octubre, 2026, el canal mantiene una actividad estable. En los últimos 30 días la variación de miembros fue de -35, y en las últimas 24 horas de 2, conservando un alto alcance.
- Estado de verificación: No verificado
- Tasa de interacción (ER): El promedio de interacción de la audiencia es 4.57%. Durante las primeras 24 horas tras publicar, el contenido suele obtener 1.17% de reacciones respecto al total de suscriptores.
- Alcance de las publicaciones: Cada publicación recibe en promedio 2 545 visualizaciones. En el primer día suele acumular 651 visualizaciones.
- Reacciones e interacción: La audiencia responde de forma activa: el promedio de reacciones por publicación es 4.
- Intereses temáticos: El contenido se centra en temas clave como javascript, css, object, html, array.
📝 Descripción y política de contenido
El autor describe el recurso como un espacio para expresar opiniones subjetivas:
“Learn to code and become a Web Developer with HTML, CSS, JavaScript , Reactjs, Wordpress, PHP, Mern & Nodejs knowledge
Managed by: @love_data”
Gracias a la alta frecuencia de actualizaciones (últimos datos recibidos el 26 octubre, 2026), el canal mantiene la vigencia y un amplio alcance. La analítica demuestra que la audiencia interactúa activamente con el contenido, lo que lo convierte en un punto de referencia dentro de la categoría Tecnologías y Aplicaciones.
fetch() is a modern JavaScript API used to make HTTP requests and communicate with servers.
It returns a Promise.
Example:
fetch("https://api.example.com/users")
.then(response => response.json())
.then(data => {
console.log(data);
})
.catch(error => {
console.log(error);
});
Using async/await:
async function getUsers() {
try {
const response = await fetch(
"https://api.example.com/users"
);
const data = await response.json();
console.log(data);
} catch (error) {
console.log(error);
}
}
Interview Tip:
fetch() rejects its Promise for network-level failures, but an HTTP error such as 404 or 500 does not automatically reject it. You should check response.ok.
72. What is AJAX?
AJAX stands for Asynchronous JavaScript and XML.
It is a technique for communicating with a server and updating parts of a webpage without reloading the entire page.
Despite the name, AJAX doesn't require XML. Modern applications commonly exchange JSON.
Example:
A webpage can request:
User data → Server
↓
JSON
↓
JavaScript
↓
Update webpage
Modern Approach:
Today, fetch() is commonly used instead of the older XMLHttpRequest API.
73. What are Web APIs?
Web APIs are browser-provided interfaces that allow JavaScript to interact with browser features and the environment.
Examples include:
• fetch()
• setTimeout()
• DOM APIs
• Local Storage
• Geolocation API
• Web Workers
• Clipboard API
Example:
setTimeout(() => {
console.log("Hello");
}, 1000);
The timer functionality is provided by the host environment, such as a browser or Node.js runtime, rather than being part of the JavaScript language itself.
Interview Tip:
Don't confuse JavaScript language features with browser Web APIs.
74. What is setTimeout()?
setTimeout() schedules a function to run after a specified delay.
Example:
setTimeout(() => {
console.log("Hello");
}, 2000);
The callback becomes eligible to run after approximately 2 seconds.
Important:
The delay is not a guarantee that the function executes exactly at that time.
It may execute later if the JavaScript runtime is busy.
75. What is setInterval()?
setInterval() repeatedly schedules a function at approximately specified intervals.
Example:
const interval = setInterval(() => {
console.log("Running...");
}, 1000);
The callback runs approximately every second until the interval is cancelled.
Stop It:
clearInterval(interval);
Common Uses:
• Timers
• Polling
• Repeated UI updates
• Periodic tasks
76. What is clearTimeout()?
clearTimeout() cancels a timeout that was previously scheduled using setTimeout().
Example:
const timer = setTimeout(() => {
console.log("Hello");
}, 5000);
clearTimeout(timer);
The callback will not execute because the timeout was cancelled before it became eligible to run.
Common Use:
Useful when you need to cancel a scheduled action.
77. What is clearInterval()?
clearInterval() stops an interval created using setInterval().
Example:function* numbers() {
yield 1;
yield 2;
yield 3;
}
const generator = numbers();
console.log(generator.next());
console.log(generator.next());
Output:
{ value: 1, done: false }
{ value: 2, done: false }
After all values are consumed:
{ value: 3, done: false }
{ value: undefined, done: true }
Important:
Calling a generator function doesn't immediately execute its body. It returns a generator object.
57. What are iterators?
An iterator is an object that provides a way to access values one at a time using the next() method.
Example:
const numbers = [10, 20, 30];
const iterator = numbers[Symbol.iterator]();
console.log(iterator.next());
console.log(iterator.next());
Output:
{ value: 10, done: false }
{ value: 20, done: false }
The iterator eventually returns:
{ value: undefined, done: true }
Common Iterables:
• Arrays
• Strings
• Maps
• Sets
That's why they can be used with for...of.
for (const number of numbers) {
console.log(number);
}
58. What is destructuring assignment?
Destructuring assignment allows values to be extracted from arrays or objects and assigned to variables.
Object Example:
const user = {
name: "Deepak",
age: 25
};
const { name, age } = user;
Array Example:
const numbers = [10, 20];
const [a, b] = numbers;
Why Use It?
It makes code shorter and easier to read, especially when working with API responses and function parameters.
59. What is dynamic import?
Dynamic import allows a JavaScript module to be loaded when it is needed, instead of loading it immediately.
It uses: import()
Example:
async function loadModule() {
const module = await import("./math.js");
console.log(module.add(10, 20));
}
Important:
Unlike a static import:
import { add } from "./math.js";
dynamic imports return a Promise.
Common Uses:
• Lazy loading
• Code splitting
• Loading features only when required
• Improving initial page performance
60. What are ES6 modules?
ES6 modules provide a standard way to divide JavaScript applications into separate files.
They use export and import.
Export:
// math.js
export function add(a, b) {
return a + b;
}
Import:
// app.js
import { add } from "./math.js";
console.log(add(10, 20));
Default Export:
export default function greet() {
console.log("Hello");
}
Import:
import greet from "./greet.js";
Benefits:
✅ Code organization
✅ Reusability
✅ Encapsulation
✅ Easier maintenance
✅ Avoids unnecessary global variables
❤️ Double Tap For Part 7
-----
2.74 ₽ · /balance_helpsort() method is used to sort the elements of an array.
Sorting Strings
const fruits = ["Banana", "Apple", "Mango"];
fruits.sort();
console.log(fruits);
Output:
["Apple", "Banana", "Mango"]
Sorting Numbers
By default, sort() converts elements to strings, so a comparison function should be used for numbers.
const numbers = [10, 5, 20, 2];
numbers.sort((a, b) => a - b);
console.log(numbers);
Output:
[2, 5, 10, 20]
Descending Order:
numbers.sort((a, b) => b - a);
Interview Tip:
sort() mutates the original array.
52. What is array destructuring?
Array destructuring allows you to extract values from an array and assign them to variables.
Example:
const numbers = [10, 20, 30];
const [a, b, c] = numbers;
console.log(a);
console.log(b);
console.log(c);
Output:
10
20
30
Skipping Values:
const numbers = [10, 20, 30];
const [first, , third] = numbers;
console.log(first, third);
Output:
10 30
Default Values:
const numbers = [10];
const [a, b = 20] = numbers;
console.log(a, b);
Output:
10 20
53. What are Sets?
A Set is a collection of unique values.
Duplicate values are automatically removed.
Example:
const numbers = new Set([1, 2, 2, 3, 3]);
console.log(numbers);
The Set contains:
{1, 2, 3}
Common Methods:
const numbers = new Set();
numbers.add(10);
numbers.add(20);
console.log(numbers.has(10));
numbers.delete(20);
Convert Set to Array:
const arr = [...numbers];
54. What are Maps?
A Map is a collection of key-value pairs.
Unlike regular objects, a Map can use different data types as keys.
Example:
const users = new Map();
users.set(1, "Deepak");
users.set(2, "John");
console.log(users.get(1));
Output:
Deepak
Common Methods:
users.set(key, value);
users.get(key);
users.has(key);
users.delete(key);
users.clear();
Example:
console.log(users.has(2));
Output:
true
Map vs Object:
Map
• Any value can be a key
• Has size property
• Built-in methods
• Designed for key-value collections
Object
• Keys are primarily strings/symbols
• No built-in size
• Different object APIs
• General-purpose objects
55. What are Symbols?
Symbol is a primitive data type used to create unique identifiers.
Example:
const id1 = Symbol("id");
const id2 = Symbol("id");
console.log(id1 === id2);
Output:
false
Even though both have the same description, each Symbol is unique.
Using Symbol as an Object Property:
const id = Symbol("id");
const user = {
name: "Deepak",
[id]: 101
};
console.log(user[id]);
Common Use:
Symbols are useful when you need unique property keys that are unlikely to conflict with other properties.
56. What are generators?
Generators are special functions that can pause and resume execution.
They are created using function* and use the yield keyword.
Example: