Why we need to use stopPropagation in javascript events?

问题

There are ways of registering Events to objects in an HTML file. So this way an object is set to detect events.

In case we think 2 div elements one inside other; If i attach an onClick event to inner div; this means outer div was not attached one. So it should NOT detect the click event. Why still we need to use stopPropagation () ? since we did not attach any other event detection...

来源：https://stackoverflow.com/questions/43953228/why-we-need-to-use-stoppropagation-in-javascript-events