Web Storage (localStorage, sessionStorage, cookies)

Web Storage data is completely isolated between different origins: 1) Each origin (protocol + domain + port) has its own separate storage space, 2) Even subdomains of the same domain cannot access each other's storage, 3) This is part of the Same-Origin Policy security model, 4) HTTPS and HTTP versions of the same site are considered different origins, 5) This isolation prevents cross-site scripting (XSS) attacks from accessing storage across sites, 6) Different ports on the same domain are also considered different origins, 7) This strict isolation is crucial for web security, 8) Understanding these boundaries is essential for designing multi-domain applications.