jquery-pjax is a client-side library that combines Ajax requests with the HTML5 History API to replace page content without triggering a full browser reload. It fetches HTML fragments from the server and updates the browser URL using pushState, preserving the page layout and assets while only swapping a designated container's content. The library emits custom JavaScript events at each stage of the request lifecycle, enabling external handlers to respond to loading, success, and error states.
The project distinguishes itself through its event-driven navigation model and server-side integration. It detects the X-PJAX header on incoming requests, allowing the server to return only the inner container HTML instead of the full page layout. A versioned cache busting mechanism uses a header and meta tag to force a full page reload when server-side assets or layout change. The library also supports form serialization via Ajax, programmatic navigation through a JavaScript API, and container content reload without adding a browser history entry.
The documentation covers server configuration for header detection and fragment delivery, as well as client-side setup for lifecycle event handling and programmatic triggers.