Bad value “” for attribute “autocomplete” on element “input”: Must not be empty.

The autocomplete attribute tells the browser whether and how it should autofill a form field. The HTML living standard defines a specific set of allowed values — an empty string is not among them. When the attribute is present but empty, the browser receives ambiguous instructions: you’ve explicitly declared the attribute, signaling intent, but provided no actual directive. Different browsers may interpret this inconsistently, some treating it as on, others ignoring it, and others falling back to default behavior.

This matters for several reasons:

• Standards compliance: The WHATWG HTML specification requires autocomplete to contain either the keywords on or off, or one or more valid autofill detail tokens. An empty string satisfies none of these.
• Accessibility: Autofill helps users with motor impairments or cognitive disabilities complete forms more quickly and accurately. An ambiguous autocomplete value can interfere with assistive technologies that rely on these hints.
• User experience: Specific autofill tokens like email, tel, street-address, and current-password allow browsers and password managers to suggest the right data for the right field. Using them correctly makes forms faster and easier to complete.

This issue commonly arises when a framework or template engine outputs autocomplete="" as a default, or when a developer intends to disable autocomplete but leaves the value blank instead of using off.

How to fix it

Choose one of these approaches depending on your intent:

1. Remove the attribute if you want default browser behavior (the browser decides whether to autofill).
2. Use on to explicitly allow autofill.
3. Use off to explicitly discourage autofill (note: browsers may still autofill for login fields regardless).
4. Use a specific autofill token to tell the browser exactly what kind of data the field expects. This is the most helpful option for users.

Common autofill tokens include: name, given-name, family-name, email, username, new-password, current-password, tel, street-address, postal-code, country, and cc-number. You can find the full list in the WHATWG autofill specification.

Examples

Incorrect: empty autocomplete value

<input type="text" name="username" autocomplete="">

This triggers the validation error because the attribute is present but contains no valid token.

Correct: remove the attribute entirely

If you have no specific autofill preference, simply omit the attribute:

<input type="text" name="username">

Correct: use on or off

Explicitly enable or disable autofill:

<input type="text" name="username" autocomplete="on">

<input type="text" name="search-query" autocomplete="off">

Correct: use specific autofill tokens

Specific tokens give browsers the best hints for filling in the right data. This is the recommended approach for forms that collect personal information:

<form>
  <label for="name">Full name</label>
  <input type="text" id="name" name="name" autocomplete="name">

  <label for="useremail">Email</label>
  <input type="email" id="useremail" name="useremail" autocomplete="email">

  <label for="phone">Phone</label>
  <input type="tel" id="phone" name="phone" autocomplete="tel">

  <label for="pwd">Password</label>
  <input type="password" id="pwd" name="pwd" autocomplete="current-password">

  <button type="submit">Sign in</button>
</form>

Using precise tokens like current-password and email helps password managers and mobile keyboards provide the most relevant suggestions, improving the experience for all users.

Learn more:

MDN Reference

MDN Web Docs: autocomplete attribute

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MDN Reference

The input element

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WHATWG Spec

Forms - WHATWG HTML Standard

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