JavaScript Guides, Tutorials & Reference

Latest guides

Custom Elements Deep Dive jsguides.dev/guides
Build reusable web components with Custom Elements v1. Define autonomous and customized built-in elements, handle lifecycle callbacks, and use Shadow DOM.

intermediate
The Dialog Element jsguides.dev/guides
Build native modal dialogs with the HTML dialog element. Open, close, and control dialogs with JavaScript, plus backdrop styling and form integration.

beginner
The Popover API jsguides.dev/guides
Build floating UI with the Popover API. Covers popover attribute, showPopover/hidePopover/togglePopover methods, beforetoggle events, and light-dismiss.

beginner
View Transitions API jsguides.dev/guides
Smooth DOM-to-DOM animations with the View Transitions API. Covers startViewTransition, CSS pseudo-elements, types, and cross-document transitions.

beginner
Broadcast Channel API jsguides.dev/guides
Send messages between browser tabs, windows, and workers on the same origin using the Broadcast Channel API. Simple messaging without postMessage targets.

intermediate

Name	Section	Description
`TextDecoder`	Built-in Objects	Decodes raw byte data into strings using the Encoding API — handles UTF-8, streaming chunks, and fatal mode.
`TextEncoder`	Built-in Objects	Encodes JavaScript strings into UTF-8 byte sequences using the standard Encoding API.
`Intl`	Built-in Objects	Namespace for the ECMAScript Internationalization API — language-sensitive formatting of numbers, dates, collators, lists, and more.
`URLSearchParams`	Built-in Objects	Read and modify query string parameters in URLs using the URLSearchParams API.
`FinalizationRegistry`	Built-in Objects	A built-in object that registers cleanup callbacks invoked when registered values are garbage-collected.
`WeakRef`	Built-in Objects	Hold weak references to objects, letting garbage collection reclaim memory when references are no longer needed.

Why JavaScript docs need clear runtime examples jsguides.dev/articles
JavaScript documentation becomes more useful when examples show real runtime behavior instead of only abstract API descriptions.

6 min read · March 12, 2026