htmx is a client-side JavaScript library that enables dynamic web page behavior directly in HTML via custom attributes (hx-get, hx-post, hx-trigger, hx-swap, etc.). It allows developers to make AJAX requests, trigger CSS transitions, manage WebSocket and Server-Sent Events, and handle browser history without writing JavaScript. The library is a single-file IIFE (~5000 lines) with no external dependencies, exposing a global htmx object with a rich public API and a configurable extension system. Its architecture is event-driven: every action (trigger, request, swap, error) dispatches custom events that can be intercepted and customized. The core pipeline includes trigger parsing, AJAX request issuance, response handling with multiple swap strategies (innerHTML, outerHTML, beforebegin, etc.), and history management via sessionStorage. htmx is designed for hypermedia-driven applications, promoting server-rendered HTML over JSON APIs. The repository also includes a comprehensive test suite (Mocha/Chai/Sinon), a Zola-based documentation website, and a set of official extensions (response-targets, preload, SSE, WebSocket, etc.) that are now maintained separately. The codebase is actively maintained with frequent releases (v2.0.11 as of late 2026) and a large community.
hastscript is a utility for creating Hast (HTML Abstract Syntax Tree) trees using a hyperscript-like API. It provides two main functions, `h` for HTML and `s` for SVG, which accept CSS-like selectors, properties, and children to construct virtual DOM nodes. The library is designed to be used in build tools and frameworks that work with the Hast syntax tree, such as those in the Unified collective. The core of the library is the `createH` function in `lib/create-h.js`, which is a parameterized hyperscript function that can be adapted for different domains (like HTML or SVG) by providing a schema and default tag name. Additionally, the library supports JSX via automatic and classic runtimes, implemented in `lib/create-automatic-runtime.js` and wired up in `lib/index.js`. The project is well-maintained, with recent commits and active CI workflows, and shows low technical drift with up-to-date dependencies.