JavaScript Study Notes

JavaScript

An essential programming language for web applications, enabling interactive HTML documents.

var keyword

Used in JavaScript for declaring global or local function-scoped variables.

let keyword

Used in JavaScript for declaring block-scoped local variables.

JavaScript Function

A block of code designed to perform a particular task. Can be assigned to variables or declared using `function name(parameters) {...}` syntax.

Strict Equality (===)

Compares two values for equality without type coercion (value and type must be the same).

Strict Inequality (!==)

Compares two values for inequality without type coercion (true if value or type are different).

Simple Data Types (JavaScript)

Includes Numbers, Strings, and Booleans.

Objects (JavaScript)

Complex data types, where functions are also considered objects. Properties can be accessed via dot notation or bracket notation.

Constructors

Functions used with the `new` keyword to create and initialize objects, typically defined with uppercase names.

ES6 Classes

A syntax introduced in ECMAScript 2015 (ES6) for defining constructors and methods using the `class` keyword.

try...catch statement

Used for exception handling; `try` executes a block of code, and `catch` handles any errors thrown within that block.

throw keyword

Used to initiate a custom exception, stopping the function execution and transferring control to the nearest `catch` block.

JavaScript Array

A dynamic-sized, ordered list-like object that can store multiple values, manipulated using methods like `push` and `splice`.

Client-Side JavaScript

JavaScript that executes in a web browser, allowing for interactive HTML documents and dynamic content changes via the `

jQuery

A fast, small, and feature-rich JavaScript library that simplifies DOM manipulation, event handling, animation, and AJAX.

$(document).ready()

A jQuery method that ensures a function is executed only after the DOM is fully loaded and parsed, making it safe to manipulate.

Event Handling

The process of attaching actions or functions to HTML elements that respond to user interactions (e.g., click, focus, change) using methods like `on`.