<p>Test form</p>
<form id="form">
  <input type="text" placeholder="first input">
  <input type="text" placeholder="second input">
  <button id="innerButton" type="submit">Inner button</button>
</form>
<button id="outerButton">Outer button</button>

var formElem = document.querySelector('#form');
var innerButtonElem = document.querySelector('#innerButton');
var outerButtonElem = document.querySelector('#outerButton');

formElem.addEventListener('submit', (event) => {
    console.log('formElem', event);
})

innerButton.addEventListener('submit', (event) => {
    console.log('innerButton submit', event);
})

innerButton.addEventListener('click', (event) => {
    console.log('innerButton click', event);
})

outerButtonElem.addEventListener('click', (event) => {
    console.log('outerButton', event);
  formElem.submit();
})