diferencia entre E.PreventDefault y E.StopPropagation y Devuelve Falso

return false does 3 separate things when you call it:

event.preventDefault()
//It stops the browsers default behaviour (like a href event on a link).

event.stopPropagation()
//It prevents the event from propagating (or “bubbling up”) the DOM.

Stops callback execution and returns immediately when called.
Dark Dotterel