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Dharan Ganesan
Dharan Ganesan

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Day 78: Web Storage

🌐 What is the Web Storage API?

The Web Storage API comprises two mechanisms: localStorage and sessionStorage. These are ways to store key-value pairs in a web browser.

  • localStorage: Offers persistent storage that persists even after the browser is closed and reopened. Data stored here remains until explicitly removed by the application or the user.
  • sessionStorage: Provides session-based storage where data persists for the duration of the page session. Once the user closes the tab or browser, the data is cleared.

Basic Usage:

// Storing data in localStorage
localStorage.setItem('key', 'value');

// Retrieving data from localStorage
const value = localStorage.getItem('key');

// Removing data from localStorage
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Advantages of Web Storage API:

  1. Simple Interface: Offers an easy-to-use key-value pair storage system.
  2. Large Storage Capacity: Allows for more significant data storage compared to cookies.
  3. Better Security: Data stored in the Web Storage API is not transmitted to the server with every HTTP request, enhancing security.


  1. Data Serialization: Objects can be stored by serializing them using JSON.stringify and deserialized using JSON.parse.
  2. Error Handling: Always handle exceptions when working with Web Storage to prevent the application from crashing due to storage limitations or security issues.
  3. Clear Outdated Data: Regularly clear unused or outdated data to optimize storage and maintain efficiency.

Best Practices:

  1. Encrypt Sensitive Data: If storing sensitive information, consider encrypting it before saving it in the Web Storage.
  2. Graceful Degradation: Always ensure your application gracefully handles scenarios where Web Storage may not be available or accessible.
  3. Consistent Data Structure: Maintain a consistent structure for stored data to ease retrieval and manipulation.

Comparing Web Storage Options:

Here's a comparison between localStorage and sessionStorage:

Feature localStorage sessionStorage
Scope Origin-specific Tab or window-specific
Persistence Survives browser close Cleared at the end of session
Storage Larger storage capacity Limited storage capacity
Accessibility Accessible from any window/tab Accessible only within the tab
Security Relatively secure More secure
Expiration Does not expire unless cleared Cleared when the session ends
Usage Long-term data storage Short-term data storage

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