Glossary
What is browser extension?
A small program that adds behaviour to your browser.
Extensions are bundles of web code with access to a restricted set of browser APIs, granted through declared permissions the user approves at install time.
They run in several separate contexts: a background service worker, optional content scripts inside pages, and the popup UI.
Because each context is isolated, extensions that read page content must explicitly inject a script into the page rather than reaching in from the popup.
In practice
A password manager reads a login form through a content script and stores vault data in the background worker.
Common questions
- What does browser extension mean in one sentence?
- A small program that adds behaviour to your browser.
- Why does browser extension matter when you use Claude or ChatGPT?
- Because each context is isolated, extensions that read page content must explicitly inject a script into the page rather than reaching in from the popup.
- Can you give an example of browser extension?
- A password manager reads a login form through a content script and stores vault data in the background worker.
Related terms
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