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Real time collaborative web applications must let many users edit shared state simultaneously over unreliable networks without ever diverging. Operational transformation (OT), the dominant production approach, achieves this through a central server that rewrites concurrent edits, which limits scalability and complicates offline use. Conflict-free replicated data types (CRDTs) guarantee convergence without a central authority, but naive implementations suffer from heavy metadata, unbounded tombstones and costly full-state synchronisation. This paper presents a browser-oriented CRDT framework that combines a run-length encoded replicated growable array for text, observed-remove map and register types for structured state, delta-state synchronisation driven by version-vector digests over WebSocket and WebRTC, and a persistence layer with snapshotting and version-vector-safe garbage collection. Evaluated on an emulated testbed with up to 64 clients against a server side OT implementation, a last-writer-wins baseline and a naive per character CRDT, the framework converged remote edits in 94 ms (median) and 146 ms (99th percentile) at 16 clients, sustained 41,000 operations per second, stored a 500,000-operation document at 1.9 times its content size, and reconciled a ten minute partition in 171 ms with 104 KB exchanged. No divergence was observed across 1.2 million randomised interleavings. Practical guidance for adopting the framework is provided.