Event Bubbling & Capturing

element.addEventListener('click', handler, {
  capture: true,
  once: true,
  passive: true
});

capture and once
passive and once
capture and passive
capture, passive, and once
The combination of capture, passive, and once provides optimal performance and behavior control: capture ensures the listener runs in the capturing phase, passive tells the browser the listener won't call preventDefault() (improving scroll performance), and once ensures the listener is automatically removed after firing once. This combination is particularly useful for initialization code that needs to run early (capturing phase) and only once, while maintaining good performance on mobile devices.