Be careful when using buttons without a "type" attribute

Be careful when using buttons without a type attribute, since browsers will consider them the default submit button of a form.

Suppose you have this form:

<form action="/save">
  <input type="text" />
  <button onclick="alert('Alert!')">Alert</button>
  <button type="submit">Save</button>
</form>

If you press the enter key inside in the text input, browsers will trigger the first button and show the alert.

To fix this, add a type="button" attribute to the first button.