Introduction to JavaScript

Overview of JavaScript

• High-level, interpreted, and object-based programming language.
• Core technology of the World Wide Web, along with HTML and CSS.
• Primarily used for creating interactive and dynamic web content.

Features of JavaScript

• Cross-platform, lightweight, and open-source language.
• Supports both client-side and server-side scripting.
• Responsible for interactivity and responsiveness of web pages.
• Interpreted within web browsers like Chrome, Firefox, and Internet Explorer.
• Shares syntax and structure with the C programming language.
• Case-sensitive with no specific hardware or OS dependency; runs inside HTML documents.
• Can be directly embedded into HTML pages.

Comparison: JavaScript vs. Java

• JavaScript is interpreted; Java is compiled.
• JavaScript has more flexible syntax and looser data types; Java requires strict typing.
• Functions are the main construct in JavaScript, while classes are prominent in Java.

JavaScript HTML Methods

• getElementById() is a commonly used method for interacting with HTML elements.

JavaScript Arithmetic Operators

• Addition: let sum = 10 + 5; results in sum being 15.
• Subtraction: let difference = 10 - 5; results in difference being 5.
• Multiplication: let product = 10 * 5; results in product being 50.
• Division: let quotient = 10 / 5; results in quotient being 2.
• Modulus: let remainder = 10 % 3; results in remainder being 1.

JavaScript Expressions

• An expression is a code unit that evaluates to a value.
• Types of expressions include:
  • Primary Expressions: Simple literals, variable references, and keywords.
  • Object and Array Initializers: Create objects or arrays using literal notation.
  • Function Definition Expressions: Define functions returning a newly defined function.
  • Property Access Expressions: Access object properties or array elements using dot or bracket notation.
  • Invocation Expressions: Call functions using their syntax.
  • Object Creation Expressions: Create instances using the new keyword.

Control Structures in JavaScript

• if statement evaluates a condition and executes based on its truthiness.
• if-else statement executes alternative blocks based on a condition.
• switch statement selects among multiple blocks based on different conditions.

Loop Control Statements

• continue statement skips the current iteration and continues the loop.
• Loops can encompass various types, allowing iteration over elements.

Arrays in JavaScript

• An array can store multiple values in a single variable.
• Example: const cars = ["Saab", "Volvo", "BMW"];
• Accessing elements by index is straightforward, e.g., cars[0] for the first element.
• Adding elements is commonly done with the push() method, e.g., fruits.push("Lemon");.

JavaScript Functions

• Functions encapsulate code for specific tasks and are invoked when needed.
• Defined using the function keyword followed by a name and parameters if required.
• Example of creating a function:

  var sum = function(x, y) {
      return x + y;
  };
  

This quiz covers the basics of JavaScript, a high-level, interpreted programming language essential for web development. It explores its core features and functionalities that enable the creation of interactive and dynamic web content. Perfect for beginners looking to understand the fundamentals of this versatile language.