Warning Button inside a form with no type attribute

Example

<!-- Flagged: this button submits the form, maybe unintentionally -->
<form>
  <input type="text" name="q">
  <button>Clear</button>
</form>

<!-- Right: be explicit -->
<button type="button">Clear</button>
<button type="submit">Search</button>

Why it matters

A <button> element defaults to type="submit" whenever its type attribute is omitted — this is spec-defined behavior, not a bug, but it surprises a lot of developers who assume a bare <button> is inert until wired up with JavaScript. The common failure mode: a "clear," "cancel," or icon-only button is added inside a form for some other purpose, gets no explicit type, and ends up submitting the form whenever it's clicked — often triggering a page reload or an unwanted API call. This is especially easy to miss during development if the form doesn't yet have a working submit handler to make the accidental submission obvious.