JavaScript Basics

What is JavaScript?

JavaScript is a high-level, dynamic, untyped, and interpreted programming language. It is a core technology of the World Wide Web, alongside HTML and CSS. JavaScript enables interactive web pages and is an essential part of web applications.

JavaScript Syntax

JavaScript syntax refers to the set of rules that define a correctly structured JavaScript program. Below are some basic syntax examples:

                // This is a single-line comment
                /*
                 This is a multi-line comment
                */

                console.log("Hello, World!"); // Outputs text to the console
                

Variables

Variables are containers for storing data values. In JavaScript, you can declare variables using var, let, or const.

                let name = "John"; // String
                const age = 30; // Number
                var isStudent = true; // Boolean
                

Data Types

JavaScript supports several data types:

• String
• Number
• Boolean
• Object
• Array
• Null
• Undefined

                let str = "Hello";
                let num = 100;
                let isActive = true;
                let obj = { name: "John", age: 30 };
                let arr = [1, 2, 3];
                

Functions

A function is a block of code designed to perform a particular task. Functions are executed when they are invoked (called).

                function greet(name) {
                    return "Hello, " + name;
                }

                console.log(greet("Alice")); // Outputs: Hello, Alice
                

Best Practices

Follow these best practices:

• Use let and const instead of var.
• Use descriptive variable names.
• Keep your code DRY (Don't Repeat Yourself).
• Comment your code for clarity.
• Use strict equality (===) instead of loose equality (==).