当'模糊'事件发生时,我怎样才能找出哪个元素焦点*到*？

document.querySelectorAll('input').forEach(function(element) {
  element.addEventListener('focus', function() {
    console.log('Focused element: ' + element.tagName);
  });
});

<form onsubmit="event.preventDefault()">
 <input type="text" id="username-input" />
 <input type="password" id="password-input" />
 <input type="submit" value="Submit" />
</form>

document.getElementById('username-input').addEventListener('focus', function() {
  console.log('Username input field clicked');
});

document.getElementById('password-input').addEventListener('focus', function() {
  console.log('Password input field clicked');
});

document.getElementById('submit-button').addEventListener('click', function() {
  console.log('Submit button clicked');
});