Implicit form submission doesn't work always

If a form submits by pressing ENTER on a focused input field this is an implicit form submission.

But does every HTML form submit on ENTER?

HTML forms implicitly submit under two conditions:

• the form has a submit button.
• the form has only one input element.

So let me share a quick example:

<form onsubmit="alert(1)">
  <!-- this will alert if you press `ENTER` while "foo" is focused -->
  <input name="foo" />
</form>

<form onsubmit="alert(2)">
  <!-- this won't -->
  <input name="foo" />
  <input name="bar" />
</form>

Tip: if you want to work around this behavior, you can always add a hidden submit button. And if you want to read the spec defining form submissions, here we go.

Edit: It turns out that there are many more corner cases — check this post post if you want to dive deeper into forms, pressed ENTER keys and form submissions.