labStorage Basics.

Theory. The browser has Web Storage: a small key → string table that survives a reload. It has four main methods: getItem(key), setItem(key, value), removeItem(key), clear(). Values are ONLY strings (that is why JSON for objects).

IMPORTANT in Code Lab: the sandbox has no access to the real localStorage. All lessons use window.labStorage — the same API, but in isolated memory for the lesson. On a real page you would write localStorage with the same calls. Do NOT write localStorage in these tasks — you will get an error.

Small examples:

window.labStorage.setItem("lang", "bg");
window.labStorage.getItem("lang");   // "bg"
window.labStorage.getItem("nope");   // null  (missing key)
window.labStorage.getItem("empty");  // ""    (key with an empty string)
window.labStorage.removeItem("lang");

null and "" are DIFFERENT: null means "no record", "" means "a record exists but is empty".

Do not store passwords, tokens, or personal secrets in browser storage — any script on the page can read them.

Common mistake: if (!getItem(k)) — mixes missing and empty; saving a number without String; localStorage instead of labStorage here.