JavaScript Basics made easy for beginners

Learn the basics of JavaScript, from data types and variables to DOM interactions and functions, through hands-on practice building an interactive input form and dynamic arrays.

Preview the project we'll build. Learn core JavaScript basics—arrays, objects, data types, and functions—plus debugging and using the included source code to create your own app.

Explore JavaScript basics and learn to use Chrome dev tools to inspect HTML, add JavaScript to pages, and view console output within the browser.

Learn how to add JavaScript to HTML pages using inline attributes, script tags, and external files, and use console.log to communicate from JavaScript to the browser when users click buttons.

Learn to use console.log and dev tools for debugging JavaScript, view outputs in the console, and add comments to explain and annotate your source code.

Learn how to use variables in JavaScript by storing strings, numbers, and booleans, checking types with typeof, and applying naming rules like camelCase and valid variable names.

Explore JavaScript data types, including strings and numbers, and distinguish not defined from undefined, plus null. See how declaring and assigning variables changes their values and types.

Explore built-in JavaScript interactions with alerts and prompts, write to the document, and manipulate the DOM via getElementById, innerHTML, and innerText.

Write a JavaScript file that prompts for a name and shows a welcome message on the page. Learn variable declaration, prompt usage, selecting an element by id, and string concatenation.

Explore JavaScript operators, including assignment, arithmetic, modulus, and string concatenation, with practical examples using variables like a. Learn increments, decrements, and how the console evaluates expressions.

Explore JavaScript conditional operators by comparing values with equality, relational, and logical operators; learn how booleans and type-aware comparisons affect true/false results, paving the way to conditionals and functions.

Explore how JavaScript functions boost control over code by wrapping logic, passing arguments, and returning values, with practical examples using alerts, prompts, and on click events.

Explore advanced functions in javascript, including type checks for strings, early returns, anonymous functions, and understanding global versus local scope.

Explore how to use conditionals in JavaScript to control program flow with if and else statements, wire prompts and questions, and handle various input values.

Learn to get input values in JavaScript by creating a text input with an id, sending its value to a function, and displaying it in the output.

Explore the switch statement in JavaScript, using cases, breaks, and a default to evaluate an expression, wrap it in a function, and return the result.

Learn to build a simple input-and-button flow that sends user input to a function, retrieves canned responses from the server, and displays the matched reply or a default message.

Explore how for loops in JavaScript work with numbers, building output and preventing infinite loops by defining start, end, and numeric conversion with Number.

Explore for, while, and do-while loops in JavaScript, set starting points and increments, prevent infinite loops, and use break to exit when conditions like a > 20 occur.

Discover how JavaScript arrays hold multiple values under one variable, access by index and length, and use push, pop, shift, unshift, splice, sort, and compare to objects.

This lesson demonstrates JavaScript objects containing name-value pairs, accessing data by property names, and adding or updating properties—like capital, population, and dynamic costs—using dot or bracket notation.

Learn to use the JavaScript math object to generate random numbers and control rounding with math floor, math ceiling, and math round, producing 0–99 or 1–100 results with math random.

Learn to build a dynamic canned response system in JavaScript by creating a random item picker from an array, with a function to add new responses and update the array.