Row/Block duplicator prototype.

Duplicator.js

/**
 * Duplicate a row by the click of an
 * element. Pass a callback to grab the new
 * row and handle it how you please.
 *
 * @param {string}   selector
 * @param {Function} callback
 */
function Duplicator(selector, callback) {
    this.selector = selector;
    this.callback = callback;
    this.bindEvents();
}

/**
 * Bind the events to the element.
 *
 * @return {void}
 */
Duplicator.prototype.bindEvents = function() {
    var self = this;

    // Grab the latest elements to bind events to.
    self.element = $(self.selector);

    // Force unbind of any click events, re-bind a new
    // click event on the element.
    self.element.unbind('click').bind('click', function(e) {
        e.preventDefault();

        // Assume the row is the parent.
        var row = self.element.parent();

        // Create our new row and add it after.
        var newRow = row.clone().insertAfter(row);

        // Call our callback so we can
        // sort out the new row.
        self.callback(newRow);

        // We don't need this button anymore?
        self.element.remove();

        // Rebind duplicator events.
        self.bindEvents();
    });
};

// Example markup
<div class="row">
    <p>Stuff</p>
    <a href="#" class="duplicator">New Row</a>
</div>

// Example JS
new Duplicator('.duplicator', function(newRow) {
    newRow.find('p').html('Look I am a new row');
});