Previously, when I've had a form with a single submit button on it, I've usually not put the type="submit" attribute in there. I've never observed this causing problems, and had believed that "submit" was the default type for a button and that I could rely on this behaviour.
However, w3schools and MDN disagree on whether I am right.
Tip: Always specify the type attribute for the
<button>element. Different browsers may use different default types for the<button>element.
whereas MDN claims:
submit: ... This is the default if the attribute is not specified, or if the attribute is dynamically changed to an empty or invalid value.
Who is right and who is wrong - both according to spec, and in real browsers?