кококококомбо
<!DOCTYPE HTML>
<html>
<head></head>
<body>
<div class="a">Div 1</div>
<div class="a">Div 2</div>
<div class="a">Div 3</div>
<div class="a">Div 4</div>
<div class="a">Div 5</div>
<script>
var elements = [].slice.call(document.querySelectorAll('div.a'));
var listener = function () {
alert(elements.indexOf(this))
};
elements.forEach(function (element) {
element.addEventListener('click', listener)
});
</script>
</body>
</html>