Offline features are promises about what still works without a network. A service worker can serve a known shell, local storage can hold drafts, and a sync rule decides what happens if the server changed meanwhile. Installation is optional and never substitutes for a usable website.
Topics in this track
- Service Worker Offline Fallback — Cache an intentional public shell without caching private case responses.
- IndexedDB for Local Drafts — Keep an unsent inspection draft separate from an accepted server record.
- Web App Manifest and Optional Installation — Describe a useful launch surface while keeping the website usable in a tab.
- Offline Sync and Conflict Policy — Tell the user when a local edit conflicts with a newer server version.
Connect with existing lessons
Browser storage: save convenience data without storing credentials; Fetch requests: separate HTTP failure, transport failure, and cancellation; HTTP caching: validate a changed representation with an ETag.
Other broad tracks
Frontend Application Architecture; Backend and API Systems; Data Persistence; Media and Live Updates; Deployment and Scale; Content Discovery and Structure.
Practice path
After the four lessons, build Project: offline inspection draft and photo intake and take Web Development: offline and delivery contracts quiz.
Further connections
Browser Capabilities and Permission Lifecycle; Permission Request Timing and Manual Fallback; Geolocation Accuracy, Cancellation, and Retention.