In HTML5 Web Storage, how do the localStorage and sessionStorage objects differ in terms of lifetime and scope of the stored key value data?

Introduction / Context:
Both localStorage and sessionStorage are part of HTML5 Web Storage and provide simple key value storage in the browser. However, they are designed for different lifetimes and scopes. Interview questions often focus on this difference because choosing the wrong storage type can lead to unexpected loss of data or unnecessary persistence of temporary information in web applications.

Given Data / Assumptions:
We are using HTML5 compatible browsers that support Web Storage.localStorage and sessionStorage have the same programming interface but different lifetimes.The question asks specifically about how long the stored data lives and how it is scoped.We assume that both stores are origin based, tied to protocol, domain, and port.

Concept / Approach:
localStorage is designed for longer term storage on the client. Once a key value pair is written, it remains available for the same origin even after the browser window is closed and reopened, until the data is removed explicitly or cleared by the user. sessionStorage is designed for per tab or per window sessions. Its data is available only for the lifetime of the specific page session and is cleared when the tab or window is closed or refreshed in a way that ends the session context. Both are client side and both store string values internally but can be used with serialized JSON for complex data.

Step-by-Step Solution:
First, recall that both storage objects provide methods such as setItem and getItem and are accessed through the window object.Next, remember that localStorage keeps its data even after you close and reopen the browser, as long as you visit the same origin.Then, note that sessionStorage data disappears when the user closes the browser tab or window associated with that session.After that, examine the answers for a statement that clearly contrasts persistent behavior across restarts with per session behavior.Finally, recognize that option A accurately describes this difference, while the other options either talk about sharing across domains, data types, server side storage, or encryption, which are not correct.

Verification / Alternative check:
You can verify this behavior by opening developer tools, writing a value to localStorage, closing the browser, reopening it, and visiting the same site. The value will still be present. If you perform the same test with sessionStorage, the values will disappear once the tab is closed. This practical experiment confirms that lifetime and session scope are the key differences, which matches the description in option A.

Why Other Options Are Wrong:
Option B is incorrect because both storage objects are scoped to a single origin and are not shared across domains or restricted only to secure sites by default. Option C is wrong because both localStorage and sessionStorage store string values; developers can convert other types to and from strings as needed. Option D falsely claims that localStorage is server side, but both are client side features. Option E suggests automatic encryption differences that do not exist; neither storage type encrypts data by default and both must be protected through general security practices.

Common Pitfalls:
Developers sometimes use localStorage for temporary data that should not persist, which can create privacy or correctness issues. Others rely on sessionStorage for data that must survive across tabs or browser restarts, leading to confusing user experiences when data disappears. A further pitfall is storing sensitive information such as tokens in Web Storage without understanding cross site scripting risks. Clear understanding of how long data remains available and where it is scoped helps avoid these mistakes when designing web applications.

Final Answer:
The correct answer is: localStorage persists across browser restarts for the same origin, while sessionStorage is cleared when the page session or tab is closed.