sample: detecting event target from event object
by sii_side
HTML
<div style="width:300px; height:300px;">
<p>ppp<a href="#">aaa</a>ppp</p>
</div>
JavaScript
document.querySelector("div").addEventListener("click", function(e) {
console.log("発生源: " + e.target.tagName);
console.log("現在: " + e.currentTarget.tagName);
if(e.target.tagName !== "A") {
window.alert("click!");
}
}, false);