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Tutorials

A growing collection of over 410 short, focused, and opinionated videos and articles about HTML, CSS, JavaScript, and more. New tutorials are added often.

🧠 Multiple formats for different learning styles. Tutorials include both written text and streaming HD videos (with captions). Watch or read on any device.

Getting Started
  • What is JavaScript? - The scripting language of the web.
  • Loading JavaScript? - How to run JavaScript in the browser.
  • Comments - How to create comments in your JS.
  • Developer Tools - How to debug JavaScript.
  • Semicolons - Indicate the end of a task.
  • Text Editors - Which one to use.
  • Planning - Start your code on paper.
APIs
  • fetch() - Make Promise-based HTTP request.
  • Response.ok - How to catch errors with fetch() calls.
  • HTTP Methods - Verbs that describe what your API calls will do.
  • Sending Data - How to include data with a fetch() request.
  • Including Cookies - How to send cross-domain cookies with fetch().
Accessibility
  • A11Y - What is A11y?
  • Keyboard Navigation - Navigating with a keyboard instead of a mouse.
  • Screen Readers - Screen readers announce the text on a page out loud.
  • Accessible Images - Add descriptive text for your images.
  • CSS-Only Components - JavaScript is sometimes required for accessibility.
  • HTML Semantics - HTML elements convey information.
  • Focus - How keyboard users interact with elements.
  • ARIA - What is is, and when to use it (or not).
  • Hiding Content - different ways to hide content in a UI.
  • Dynamic UI - How to announce dynamic UI changes to screen readers.
  • Button State - How to communicate button state to screen readers.
  • Status Messages - Short-lived notifications about state changes.
Arrays
  • Array.map() - Transform the items in an array and create a new one.
  • Array.filter() - Create a new array containing a subset of items from an existing ones.
  • Array.reduce() - Take the content of an array and return a single value.
  • Array.reverse() - Reverse the order of items in an array.
  • Array.sort() - Sort and reorder the items in an array.
  • Array.join() - Combine all items in an array into a string.
  • Array.push() - Add items to an array.
  • Array.concat() - Merge two or more arrays together.
  • Array.slice() - Copy a segment of an array into a new array.
  • Array.splice() - Delete, replace, and add items to an array at specific indexes.
  • Array.shift() - Remove the first item from an array.
  • Array.pop() - Remove the last item from an array.
  • Array.from() - Create a new array from an existing array or array-like object.
  • Array.includes() - Check if an array includes an item.
  • Array.some() - Check if at least one item in an array matches some criteria.
  • Array.every() - Check if every item in an array matches criteria.
  • Array.indexOf() - Get the index of the first matching item in an array.
  • Array.find() - Get the first item in an array that satisfies a condition.
  • Array.findIndex() - Find the index of an item in a multidimensional array.
  • Shuffling Arrays - Randomly shuffle the items in an array.
Browser Storage
  • localStorage - Store data locally in the browser for later use.
  • sessionStorage - Store data locally until the browser session ends.
  • Storage Limits - Storage limits vary by browser.
  • Browser Storage & Dev Tools - Debug localStorage and sessionStorage.
Classes, Styles & Attributes
  • Element.classList - Add, remove, toggle, and check for classes on an element.
  • Element.className - Get and set classes on an element.
  • Element.style - Get and set inline styles for an element.
  • Window.getComputedStyle() - Get the computed style of an element.
  • Element Attribute Methods - Get, set, remove, and toggle attributes.
  • Element Properties - Read and write properites on an element.
  • Attributes vs. Properties - What’s the difference, and which should you use?
  • Element.getBoundingClientRect() - Get information about the size of an element and its position relative to the viewport.
  • window.innerWidth - Get the width of the viewport.
  • window.innerHeight - Get the height of the viewport.
Cloudflare Workers
  • Getting Setup - How to sign up for Cloudflare Workers (it’s free!).
  • Creating your first serverless function - A step-by-step guide.
  • Security - How to secure serverless functions.
  • HTTP Methods - Verbs that describe the request you’re making.
  • Request Data - How to get data from an HTTP request.
  • Databases - How to store data in a serverless database.
  • Structuring Functions - How to structure and modularize serverless functions.
Conditionals
  • if/else - Check if a condition is true.
  • and/or - Check if one or more conditions are true.
  • Comparisons - Compare numbers and strings.
Constructor Pattern
  • The Constructor Pattern - What a constructor pattern is, and why you’d use it.
  • new Constructor() - How to create a Constructor pattern instance.
  • Methods - How to add methods to a Constructor instance.
  • Static Methods - How to attach methods to the library object.
  • Chaining - How to chain multiple methods together.
  • Options & Settings - Let developers modify how a library works.
Cookies
  • Cookies - What they do, and some local dev caveats.
  • document.cookie - Set a cookie value.
  • getCookie() - Get a cookie value.
  • max-age - Delete a cookie value.
DOM Injection
  • document.createElement() - Create an element.
  • Element.before() - Insert an element into the DOM before another one.
  • Element.after() - Insert an element into the DOM after another one.
  • Element.append() - Insert an element at the end of a set of elements inside a shared parent.
  • Element.prepend() - Insert an element at the beginning of a set of elements inside a shared parent.
  • Element.remove() - Remove an element from the DOM.
  • Element.replaceWith() - Replace an element with another.
  • Node.clone() - Create a copy of a node.
DOM Traversal
  • Element.parentNode - Get the parent of an element.
  • Element.closest() - Get the closest parent element that matches a selector.
  • Element.children - Get the immediate descendant elements of an element.
  • Element.childNodes - Get the immediate descendants of an element, including text fragments and other non-element nodes.
  • Node.firstChild & Node.lastChild - Get the first and last child nodes of a parent element.
  • Node.firstElementChild & Node.lastElementChild - Get the first and last child element of a parent element.
  • Node.nextSibling & Node.previousSibling - Get the next and previous sibling node of an element.
  • Node.nextElementSibling & Node.previousElementSibling - Get the next and previous sibling element of an element.
Dates & Times
  • new Date() - Create a new Date object.
  • Unix Timestamps - A more consistent way to track time across systems.
  • Date Details - How to get details about a date.
  • Date.prototype.toString() - Get the Date as a string.
  • Date.prototype.toLocaleString() - Get a formatted date string.
  • UTC Time - Get a date’s UTC time details.
  • Modify Date Details - Set and update Date object properties.
  • Add & Remove Time - Add and remove time from a Date object.
  • Dates & Immutability - How to create immutable Date objects.
  • Date.now() - Get a Unix Timestamp for right now.
  • Date.parse() - Get a Unix Timestamp for a date string.
  • Date Pain Points - Challenges working with dates.
  • Date Libraries - Lightweight tools for complex date work.
ES Modules
  • Overview - What ES modules are, and how they work.
  • In the Browser - A few gotchas around native ES modules.
  • export - Export code for use in other files.
  • import - Import code from other files.
  • default exports - Export a single value.
  • Renaming Things - Rename functions and variables in ES modules.
  • Side Effects - Run code automatically in an ES module.
  • Nested Modules - How to structure ES modules.
  • Scope - ES modules are scoped by default.
  • Bundling & Tree-Shaking - Improve the performance of ES modules in the browser.
End-to-End Testing
  • Overview - Verify that all of the different pieces of your site work together.
  • Installing Playwright - An end-to-end testing library.
  • Testing Locally - Define a local server to run development tests.
  • Writing & Running Tests - How to write and run end-to-end tests.
  • Organizing Tests - How to keep end-to-end tests organized.
  • A Few Details - A few small details to keep in mind.
Event Listeners
  • Element.addEventListener() - Listen for events on an element.
  • Event delegation - Easily listen for events on multiple elements.
  • useCapture - How to detect events that don’t bubble.
  • Named Callback Functions - Running the same function for multiple events.
  • Custom Events - Provide event hooks for developers.
  • Debouncing - Provide event hooks for developers.
Extract & Copy Properties
  • Array Destructuring - Extract variables from array properties.
  • Object Destructuring - Assign variables from object properties.
  • Spread Syntax - Expand array or object properties into their own values.
  • Spread & Function Arguments - Pass in an array of arguments as individual values.
  • Spread & New Objects - Use the spread operator to copy and merge objects.
FormData
  • new FormData() - Serialize form fields into key/value pairs
  • Loop FormData - How to loop over FormData values.
  • FormData.get() & FormData.getAll() - Get FormData values.
  • FormData.set() - Set a FormData value.
  • FormData.append() - Add FormData values.
  • FormData.delete() - Delete FormData values.
  • FormData.has() - Check for a FormData value.
  • FormData.keys() - Get a collection of FormData keys.
  • FormData.values() - Get a collection of FormData values.
  • Serializing FormData - Convert FormData into an object or query string.
Functions
  • Writing a Function - What a function is, and how to write one.
  • Parameters & Arguments - How to pass values into a function.
  • Returning a Value - How to get values from a function.
  • Default Parameters - Define default values for function parameters.
  • The arguments keyword - Get all of the arguments passed into a function.
  • Rest Parameters - Create an array with multiple function arguments.
  • Arrow Functions - An alternate way to define functions.
HTML & Text
  • Element.innerHTML - Get and set HTML content for an element.
  • Element.outerHTML - Get and set HTML content including an element.
  • Node.textContent - Get and set the text of an element (without markup).
  • Element.innerText - Get and set the rendered text of an element.
  • Cross-Site Scripting (XSS) - What XSS attacks are, and how to avoid them.
  • Convert Arrays to HTML - Create HTML from array data.
Immutability
  • Immutability - Immutable properties and assign by reference.
  • Immutable Arrays - Create an immutable copy of an array.
  • Immutable Objects - Create an immutable copy of an object.
  • Nested Arrays & Objects - Challenges with nested arrays and objects.
  • structuredClone() - Create a deep clone of an array or object.
  • Object.freeze() - Create a deep clone of an array or object.
IndexedDB
  • indexedDB - Database storage built into the browser.
  • indexedDB.open() - Open an indexedDB database.
  • indexedDB.close() - Close an indexedDB database.
  • DB.createObjectStorage() - Create a database storage.
  • DB.transaction() - Create a collection of database operations.
  • DBStore.add() - Add items to a database store.
  • DBStore.put() - Update data in a database store.
  • DBStore.delete() - Delete data from a database store.
  • Database Upgrades - Upgrade an indexedDB database.
  • Getting Data - How to get data from an indexedDB database.
  • DBStore.get() - Get a single item from a database.
  • DBStore.getAll() - Get all matching items from a database.
  • DBStore.count() - Get the number of items in a database.
  • Combining Stores - How to combine data from multiple stores.
  • Indexes - An alternative way to reference database items.
  • Cursors - A way to step through database entries.
  • Deleting - How to delete stores and databases.
Internationalization API
  • The Intl Object - The Internationalization API parent object.
  • Locales - Define the localized language to use for formatting.
  • The Internationalization API and performance - Best practices for better performance.
  • Intl.NumberFormat - Format numbers into a variety of outputs.
  • Intl.DateTimeFormat - Format Date objects into a variety of string outputs.
  • Intl.RelativeTimeFormat - Format numbers into relative time.
  • Intl.ListFormat - Format a list of items into a language-specific string.
IntersectionObserver
  • new IntersectionObserver() - Run a callback function when an element enters or leaves the viewport.
  • The IntersectionObserverEntry Array - Get the elements that entered or left the viewport.
  • IntersectionObserverEntry.target - The element that entered or left the viewport.
  • IntersectionObserverEntry.isIntersecting - Check if the element is in the viewport or not.
  • IntersectionObserverEntry.boundingClientRect - Details about the element’s position in the viewport.
  • IntersectionObserverEntry.rootBounds - Details about the viewport.
  • IntersectionObserverEntry.intersectionRatio - The percentage of the element that’s in the viewport.
  • IntersectionObserverEntry.intersectionRect - Details about the portion of the element that’s in the viewport.
  • IntersectionObserverEntry.time - The amount of time from when the page loaded to when the intersection happened.
  • IntersectionObserver.unobserve() - Stop observing an element.
  • IntersectionObserver.disconnect() - Stop observing all elements.
  • IntersectionObserver Options - Configure how an IntersectionObserver behaves.
  • IntersectionObserver Instance Properties - Access properties on the IntersectionObserver object.
JSON
  • JSON.stringify() - Convert object or array data into a string.
  • JSON.parse() - Convert stringified JSON back into an object or array.
JavaScript Class Pattern
  • new Class {} - How to create a Class instance.
  • Static Properties - Attach properties to the Class instead of the instance.
  • Private Class Features - Keep variables and functions private.
JavaScript-Free Components
  • Disclosure - Create an expand-and-collapse disclosure element.
  • Autocomplete - Create an autocompletion text input.
  • Smooth Scrolling - Animate scrolling to anchor links.
Linting
  • Overview - Identify typos, syntax errors, and anti-patterns in your code.
  • Installing JSHint - How to install JSHint.
  • Configuring your editor - How to extend your text editor to lint your code.
  • Command Line Interface (CLI) - How to lint your code from Terminal.
  • Configure your linter - Customize your linter behavior.
  • Ignore Code - How to tell the linter to skip lines of code.
Loops
  • for - Loop through arrays and array-like objects.
  • for...of - Loop over iterable objects.
  • for...in - Loop over plain objects.
  • break and continue - Skip and end loops.
  • Array.forEach() & NodeList.forEach() - Loop through arrays and NodeLists.
Numbers
  • An intro to numbers - What a number is and how to create one.
  • parseInt() - Convert a string into an integer (whole number).
  • parseFloat() - Convert a string into a point number (a number with decimal points).
  • Number() - Convert a string into a number.
  • Number.toFixed() - Format a number to a fixed number of decimal places.
  • Number.toString() - Convert a number to a string.
  • Basic math - Do basic arithmetic with JavaScript.
  • Increment & Decrement - Increment numbers up and down.
  • Math.abs() - Get the absolute value of a number.
  • Math.floor() - Get the largest integer less than or equal to a number.
  • Math.ceil() - Get the smallest integer greater than or equal to a number.
  • Math.max() - Get the largest number from a set of numbers
  • Math.min() - Get the lowest number from a set of numbers.
  • Math.random() - Return a random float between 0 and 1.
Objects
  • Object.keys() - Get an array of keys from an object.
  • Object.entries() - Get an array of key/value pairs from an object.
  • delete - Remove an item from an object.
  • Object.assign() - Perform a shallow merge of two or more objects.
  • Object.freeze() - Make an object or array immutable.
  • Object Property Shorthand - A shorthand for defining object properties.
  • Object Function Shorthand - A shorthand for defining functions in an object.
  • Optional Chaining - Chain properties only if they’re not undefined or null.
Promises
  • Ajax - JS is synchronous by default.
  • Promises - Modern asynchronous tasks in JavaScript.
  • Promise.then() - You chain Promise.then() methods and run them at any time.
  • Promise.catch() - Handling promise errors.
  • Promise.finally() - Run a task whether a Promise resolves or not.
  • Promise.all() - Run code after all Promises resolve.
  • async and await - Wait for asynchronous code to resolve before continuing.
  • async and Promises - Async functions always return a Promise.
  • Structuring async code - You might structure async code differently.
  • try...catch - An alternate way to handle errors with async/await.
Proxies
  • new Proxy() - Detect interactions with an array or object.
  • The handler object and traps - Tell the Proxy object how to respond to interactions.
  • handler.get() - Run when a property is retrieved from a Proxy object.
  • handler.set() - Run when a property is defined or updated in a Proxy object.
  • handler.deleteProperty() - Run when a property is defined or updated in a Proxy object.
  • handler.apply() - Run when a Proxy function object is called.
  • handler.has() - Run when the in operator is used to check for a property in an object.
  • handler.construct() - Run when a constructor function is instantiated with the new keyword.
  • handler.defineProperty() - Run when the static Object.defineProperty() method is run on the Proxy object.
  • handler.getOwnPropertyDescriptor() - Run when the static Object.getOwnPropertyDescriptor() method is run on the Proxy object.
  • handler.getPrototypeOf() - Run when the static Object.getPrototypeOf() method is run on the Proxy object.
  • handler.isExtensible() - Run when the static Object.isExtensible() method is run on the Proxy object.
  • handler.preventExtensions() - Run when the static Object.preventExtensions() method is run on the Proxy object.
  • Proxies & Nesting - Handle nested arrays and objects in a Proxy.
  • Proxy Use Cases - When and why you might use Proxies.
Revealing Module Pattern
  • The Revealing Module Pattern - What a revealing module pattern is.
  • IIFE Wrapper - How to create a revealing module pattern.
  • Private Features - Keep certain variables and functions private.
Scope
  • Global Scope - Variables accessible from anywhere.
  • Scope Overview - What scope is, and how it works.
  • Lexical Scope - Variable accessibility in nested functions.
  • Updating Variables & Scope - How scope impacts defining and updating variables.
  • Block Scope - Scope and curly brackets.
  • Creating Scope - How to keep code out of the global scope.
Selectors
  • document.querySelectorAll() - Find all matching elements on a page.
  • document.querySelector() - Find the first matching element on a page.
  • Element.matches() - Check if an element would be selected by a particular selector or set of selectors.
  • Type-specific selector methods - Other selector methods.
Serverless
  • Functions-as-a-Service - What is serverless?
  • But there are servers? - Why is it called serverless if there are servers involved?
  • Vendors - Where to run serverless functions.
Service Workers
  • Overview - What Service Workers are, and how they work.
  • Security - Service Workers require an SSL certificate.
  • The Basics - Create your first Service Worker.
  • Updates - Update an installed Service Worker file.
  • event.request - Get details about the Request object.
  • Developer Tools - How to view and debug your service worker.
  • Strategies - Different approaches for using Service Workers.
  • Cache Management - How to name and delete Service Worker caches.
  • API Responses - How to cache API responses.
  • Expiring a Cache - How to expire cached items.
  • Worker.postMessage() - Trigger Service Worker actions from the browser.
  • Cleanup - Cleaning up cached data.
State-Based UI
  • What's State-Based UI - What’s state, and why would you use it?
  • State-Based UI - How state-based UI works.
  • DOM Diffing - Determine what UI changes are needed when state updates.
  • Reactivity - Automatically update the UI when state changes.
  • Components - Couple UI templates with state objects.
  • Batching Renders - Combine state changes into a single render.
  • Memoization - Hints to optimize rendering performance.
  • Virtual DOM - Representing the DOM as an object.
  • Libraries - When and why to use a state-based UI library.
  • The problem with SPAs - Why single page apps might not be the right choice.
Strings
  • An intro to strings - What a string is and how to create one.
  • String.padStart() - Add characters to the beginning of a string if it’s less than a certain length.
  • String.padEnd() - Add characters to the end of a string if it’s less than a certain length.
  • String.trim() - Remove leading and trailing whitespace from a string.
  • String.toUpperCase() - Transform all text in a string to uppercase.
  • String.toLowerCase() - Transform all text in a string to lowercase.
  • String.replace() - Replace a portion of a string with something else.
  • String.replaceAll() - Replace all instances of a string inside another string.
  • String.slice() - Get a portion of a string starting and ending at specific characters.
  • String.split() - Convert a string to an array.
  • String.indexOf() - Find the index of a substring inside a string.
  • String.includes() - Check if a string contains a substring.
  • Escaping Strings - Including quotes in your strings.
  • String Concatenation - Combining strings and splitting them over multiple lines.
  • Template Literals - More easily create multi-line or complex strings.
Testing JavaScript
  • Overview - What is JavaScript testing?
  • The goal of testing - Why should you test your code?
  • The Command Line Interface (CLI) - A primer on the Terminal window.
  • Failing Tests - Tests should fail for the right reasons.
  • Testing Strategy - The right mix of tests to run.
  • Organizing Tests - How to prevent test runners from colliding.
URL & URLSearchParams
  • new URL() - Create a new URL object.
  • URL Object Properties - Set and get URL string properties.
  • URL.toString() - Get the full URL as a string.
  • new URLSearchParams() - An object for modifying query string values.
  • Looping URLSearchParams - Loop over items in a URLSearchParams object.
  • URLSearchParams.get() & URLSearchParams.getAll() - Get query string values.
  • URLSearchParams.set() - Set query string values.
  • URLSearchParams.append() - Add query string values.
  • URLSearchParams.delete() - Delete query string values.
  • URLSearchParams.has() - Check if a query string has a value.
  • URLSearchParams.keys() - Get a collection of query string keys.
  • URLSearchParams.values() - Get a collection of query string values.
  • URLSearchParams.toString() - Get the query string as a string.
  • URLSearchParams.sort() - Sort the values in a query string.
Unit Testing
  • Overview - Verify that small chunks of code do what they’re supposed to do.
  • Installing Jest - A unit testing library for vanilla JS.
  • Writing & Running Tests - How to write and run unit tests.
  • Matcher Methods - Methods that make testing a bit easier.
  • Organizing Tests - How to keep unit tests organized.
  • Testing Coverage - Check what percentage of your code is covered by tests.
  • Testing DOM Manipulation - How to test DOM manipulation scripts.
  • Testing APIs & Async Tasks - How to test asynchronous JavaScript.
  • A Few Details - A few small details and gotchas to be aware of.
Variables
  • Defining a variable - What a variable is, and how to create one.
  • Updating a variable - Change the value of a variable.
  • let - A new way to declare variables (with scope).
  • const - Define a constant variable.
  • var, let, & const - Which approach should you use?
  • Ternary Operator - A shorter way to write if...else statements.
Web Components
  • Web Components - What Web Components are, and why you’d use them.
  • customElements.define() - Register a Web Component.
  • Lifecycle - The Web Component lifecycle events.
  • Rendering HTML - How to render HTML into the UI.
  • Customizing - Using attributes and HTML to customize Web Components.
  • Event Listeners - Listen for events in the Web Component.
  • Host Element - Get the custom element inside event listeners.
  • Disconnect Events - Stop listening to events when the custom element is removed.
  • Attributes - Detect changes to attributes.
  • Shadow DOM - A separate DOM, separate from the main DOM.
  • Slots - Placeholders inside the Web Component HTML.
  • Styling - Styling Web Components in the shadow DOM.
  • Shared Styles - How to share styles across Web Components.