Event bubbling is an event propagation type which is observed in DOM API.

<div>
  <p>
    <img> </img>
  </p>
</div>

For example suppose all 3 elements have registered to handle an event, then as per bubbling rule the event will be handled from inner to outer that is img element will handle the event first then p and last will be div element.

For general use event bubbling is convenient but some rare cases we need to handle outer event first than inner so in those situation we need to avoid event bubbling.

This is achieved by making useCapture true to the event handler function where by default it's passed as false.

btn.addEventListener('click',action item(),true);

OR

To stop bubbling we can use either

// stops immediately
event.stopImmediatePropagation()

Or

//stops after running current event
event.stopPropagation()