Edit in JSFiddle

$(function () {
	var wrapper = document.getElementById("wrapper");

    var appendit = function() {
		var div = document.createElement("div");
		var txt = document.createTextNode("Wrapped contents");
		div.appendChild(txt);
		wrapper.appendChild(div);
    }
    
    var appendit_wrapped =  _.wrap(appendit, function(wrapped) {
    
        // append Top
		var div = document.createElement("div");
		var txt = document.createTextNode("Top");
		div.appendChild(txt);
		wrapper.appendChild(div);
        
        // wrapped function.
        wrapped();
        
        // append Bottom
		var div = document.createElement("div");
		var txt = document.createTextNode("Bottom");
		div.appendChild(txt);
		wrapper.appendChild(div);

        return;        
    });

    $(".trigger").click(function(){
        appendit_wrapped();
        return false;
    });

});

<p>_.wrap Practice</p>
<div id="wrapper">
    <a href="#" class="trigger" >クリックして発動</a>
</div>

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

div.trigger2{
    color:red;
}