W3c Packages

Standard Subresource Integrity library -- parses, serializes, generates, and verifies integrity metadata according to the SRI spec.

A JavaScript implementation of many web standards

A per-spec XML serializer implementation

List of standard HTML tags

An implementation of WHATWG AbortController interface.

An implementation of WHATWG EventTarget interface.

A pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module.

Use Custom Properties Queries in CSS

Nest rules inside each other in CSS

Use Custom Media Queries in CSS

Use Custom Selectors in CSS

Use 4 & 8 character hex color notation in CSS

Use the rebeccapurple color keyword in CSS

Use the gray() color function in CSS

Convert modern CSS into something browsers understand

List of standard SVG tags.

List of known CSS properties

List of known MathML tag names

Map of web namespaces

List of HTML void tag names