File System Access and Origin-Private Storage Cheat Sheet
Work safely with user-chosen files, directories, writable streams, permissions, OPFS, worker sync handles, quotas, and cleanup.
Open cheat sheetHTML · 7 guides
Security, Storage, and Devices
Protect applications and use browser storage, identity, files, and device APIs.
Focused references
Security, Storage, and Devices cheat sheets
Each guide includes copy-ready syntax, detailed examples, and authoritative references.
HTML File Inputs and File API Cheat Sheet
Select, inspect, validate, preview, read, and upload user-chosen files with input type=file, File, FileReader, object URLs, FormData, and server-side checks.
Open cheat sheetWeb Authentication and Passkeys Cheat Sheet
Implement WebAuthn passkey registration and sign-in with correct encoding, conditional UI, user verification, and mandatory server-side validation.
Open cheat sheetWeb Crypto API Cheat Sheet
Use browser cryptographic primitives safely for randomness, hashing, authenticated encryption, signatures, derivation, and controlled key import and export.
Open cheat sheetWeb Permissions, Geolocation, and Device Access Cheat Sheet
Request geolocation, camera, microphone, display capture, and motion data with secure-context checks, meaningful consent, cleanup, and fallbacks.
Open cheat sheetWeb Security: CSP, SRI, and Trusted Types Cheat Sheet
Deploy restrictive Content Security Policy, verify third-party resources with SRI, and reduce DOM injection risk with Trusted Types and safe sinks.
Open cheat sheetWeb Storage and IndexedDB Cheat Sheet
Store browser data safely with localStorage, sessionStorage, IndexedDB transactions, indexes, quota estimates, persistence, and migrations.
Open cheat sheet