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Local Storage and Session Storage

April 5, 2026

Web Storage API

Store data in browser with higher capacity than cookies.

Storage Example

// localStorage (persists after browser close)
localStorage.setItem("user", JSON.stringify({name: "John"}));
let user = JSON.parse(localStorage.getItem("user"));
localStorage.removeItem("user");
localStorage.clear();

// sessionStorage (session only)
sessionStorage.setItem("tempData", "value");

Key Points

  • 5MB+ storage per origin.
  • Key-value pairs, strings only (JSON stringify).
  • localStorage: permanent, sessionStorage: tab session.
  • storage event for cross-tab sync.
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