Event Handling – Adding & Removing Listeners

Event listeners are added with addEventListener.

button.addEventListener('click', handleClick, { once:true, passive:true });

• type – event name (click, keydown).
• listener – function or object with a handleEvent method.
• options – capture, once, passive.

Removing:

button.removeEventListener('click', handleClick);

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Example: Delegated click handling

document.body.addEventListener('click', e => {
  if (e.target.matches('a[data-action]')) {
    console.log('Link clicked:', e.target.dataset.action);
  }
});