The evolution of web applications been going over few stages
- Web 1.0 - documents became available over HTML, cross-linked, and actionable over server side.
- Web 2.0 - Dynamic HTML allows to change the application UI without the server side trip. XHR along with DOM manipulation made this possible.
- Web 3.0 - web applications from various vendors, specialized in own functionality are meeting in same user facing application.
Along with so obvious advantages as for business as for consumer, Web 3.0 brought whole row of cross-business and cross-site challenges. Which have been addressed in series of standards and protocols. CORS, data schema versioning, 3rd party scripting tag management become a blessing for consumer and curce for web app developers.
What did not happen yet, is ability to adopt 3rd party web apps in useful and still safe for host application manner. EPA-WG with the concept of microapplication container is trying to address the challenge.
Web Components Community Group is trying to address same challenge by introducing the no-JS scoped declarative web components.