document updated 10 years ago, on Jul 24, 2014

Two things make it easier to build full-featured applications in the browser:

node.js / npm are providing industrial-strength libraries
some HTML5 features are making it possible for applications to be entirely client-side, needing no assistance from a server

This is useful for PCI-DSS and HIPAA environments, because the applications run entirely within the Javascript sandbox, and JS-sandboxed apps are usually allowed to run within a PCI/HIPAA environment.

newer HTML5 features

storage
- Web Storage, AKA localStorage [1] [2] [3]
- IndexedDB [1] [2]
- ~~Web SQL Database~~ ~~[2]~~
interaction with local files
- save local files — [1] [2]
- load local files — FileReader API [2]
- MOAR