SockJS Client

SockJS-client is a browser JavaScript library (current stable version 1.6.1) that provides a WebSocket-like object, abstracting away underlying transport mechanisms. It aims to offer a coherent, cross-browser, full-duplex communication channel between the browser and a web server, even in environments without native WebSocket support or behind restrictive corporate proxies. The library first attempts to use native WebSockets, falling back to various browser-specific transports (like streaming or polling) if necessary. Releases are somewhat irregular but active, with recent updates focusing on security fixes and dependency updates. A key differentiator is its robust fallback mechanism, adhering closely to the HTML5 WebSocket API, and supporting cross-domain connections without requiring Flash. It explicitly requires a server counterpart, such as `sockjs-node`, for functionality.