Edit in JSFiddle

$(function () {

 	var fibonacci = _.memoize(function(n) {
	  return n < 2 ? n: fibonacci(n - 1) + fibonacci(n - 2);
	});

	var buttonView = {
	onClick: function(elem){ 
        var id = elem.toElement.getAttribute("id");
        var c = elem.toElement.getAttribute("data-fibo");
        var tar = document.getElementById(id);
        var result = document.createTextNode( '=' + fibonacci(c) );
        
        return tar.appendChild(result);
    }
	};
	_.bindAll(buttonView, 'onClick');
	 
	var btn = document.querySelectorAll(".trigger");

    for(var i = 0, il = btn.length; i < il; i++) {
	  btn[i].addEventListener('click', buttonView.onClick, false);
	}

});

<p>_.memoize Practice</p>
<div id="wrapper">
<ol>
    <li class="btn"><a href="#" class="trigger" data-fibo="7" id="b1">fibonacci(7)</a></li>
    <li class="btn"><a href="#" class="trigger" data-fibo="8" id="b2">fibonacci(8)</a></li>
</ol>
</div>

p, div {
    margin: 20px 20px 0px;
    clear:both;
}

div.trigger2{
    color:red;
}