Edit in JSFiddle

<div id="DivOuter"  style="height:100px; border:2px solid red;">
    <div id="DivInner"  style="height:50px; border:2px solid green; margin-top 100px;">
        <input type="button" value="Click Me"></input>
        
    </div>
    <H3>Event Capturing</H3>
</div>

var divs = document.getElementsByTagName('div')

for(var i=0; i<divs.length; i++) {
  divs[i].addEventListener("click", showEventPropagation, true)
}
function showEventPropagation(event){
  var target = event.target || event.srcElement
   alert(this.id);
}