Preventing the default action or bubbling of events

How to cancel an event or preventing it from bubbling up the DOM tree.

jQuery offers two useful methods that may be called within events handlers in order to stop the event from happening: e.preventDefault() and e.stopPropagation()

In fact, both are plain JavaScript methods that are available on the event object of any handler function:

function handler(e) {
// stop the immediate action of this event

// prevent the event fro bubbling up

// attach handler to the keydown event of the document
if (document.attachEvent) document.attachEvent('onkeydown', handler);
else document.addEventListener('keydown', handler);

Returning false from an event handler has in most cases the same effect as calling those methods, but there are exceptions, such as form submissions (submit event).