Glossary · Internet & Web

Autofill

Autofill is a browser or password manager feature that fills in saved details such as names, addresses, card numbers and logins on web forms automatically.

Updated October 6, 2026

Autofill is a feature of browsers, password managers and phone systems that completes web form fields from information you previously saved, such as your name, address, phone number, payment card or login. It saves typing and reduces mistakes.

Why it matters

Autofill speeds up checkout and sign-in, which can raise form completion rates. It works by matching fields to saved data, and developers help it with standard autocomplete attributes. It also has security aspects: a password manager that fills only on the exact saved domain helps resist phishing, but a browser that fills hidden fields can leak data to a malicious form, so many tools ask before filling sensitive details.

Example

<input type="email" name="email" autocomplete="email">
<input type="text" name="cc-number" autocomplete="cc-number">

With these autocomplete values, the browser knows which stored details belong in each box. Without them, it may guess wrongly or skip the field.

Common mistakes

  • Disabling autofill on login forms with autocomplete="off", which blocks password managers and encourages weak, memorized passwords.
  • Using unusual field names so the browser cannot recognize them.
  • Saving payment cards in a shared computer's browser.

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