Building web components with the Custom Elements API. Covers autonomous elements, lifecycle callbacks, Shadow DOM, slots, CSS properties, and form integration.
Latest guides
View all →- Building Web Components with Custom Elements: A Deep Dive jsguides.dev/guides
- How to Use the HTML Dialog Element for Native Modals 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.
- The Popover API: Floating UI menus, tooltips, and toasts jsguides.dev/guides
Build floating UI with the Popover API. Covers popover attribute, showPopover/hidePopover/togglePopover methods, beforetoggle events, and light-dismiss.
- View Transitions API: Smooth DOM Animations in JavaScript jsguides.dev/guides
Learn to animate between DOM states with the View Transitions API. Covers startViewTransition, CSS pseudo-elements, types, and cross-document transitions.
- Using the Broadcast Channel API for Cross-Tab Messaging jsguides.dev/guides
Share data between browser tabs, windows, and workers on the same origin with the Broadcast Channel API — a simpler one-to-many alternative to postMessage.
Reference
View all →| Name | Section | Description |
|---|---|---|
Reflect.defineProperty() | Built-in Objects | Reflect.defineProperty() installs a property descriptor on an object and returns a boolean for success or failure, rather than throwing. |
Reflect.construct() | Built-in Objects | Reflect.construct() invokes a target constructor with array-like arguments and an optional new.target, the reflective equivalent of the new operator. |
Reflect.deleteProperty() | Built-in Objects | Reflect.deleteProperty() removes a property from an object and returns a boolean indicating success — the functional form of the delete operator. |
JSON.rawJSON() | JSON | JSON.rawJSON() wraps a JSON primitive so JSON.stringify emits it verbatim. Use it for lossless 64-bit integers, exact unicode escapes, and tricky JS cases. |
Set.prototype.isSubsetOf() | Map and Set | Set.prototype.isSubsetOf() returns true when every element of a Set is also in another Set or set-like object. ES2025, uses SameValueZero. |
Set.prototype.isDisjointFrom() | Map and Set | Set.prototype.isDisjointFrom() returns true when a Set shares no elements with another Set or set-like object. Added in ES2025 to modern browsers. |
Tutorial series
View all →Latest articles
View all →- Why JavaScript docs need clear runtime examples jsguides.dev/articles
JavaScript docs are more useful when examples show real runtime behavior — execution order, coercion, and environment quirks — not just abstract API surfaces.