Hi, I'm new to Umbraco and I want to know how I can handle AJAX call?

As an exemple, in MVC I do it this way 

In the view : 

function showCompanies() {
    $.post(liveString + '/Enterprises/GetAll', function(data) {
        $('#COMPANIESLIST_CONTENT').empty().append(data);
        $('#companies_list_content').cycle('destroy');
        $('#companies_list_content').cycle({
            fx: 'fade',
            timeout: 0,
            pager: '#companies-nav'
        });
    });
}

In my controller : 

   [AcceptVerbs(HttpVerbs.Post)]
        public virtual ActionResult GetAll()
        {
            var nbMaxItemCol = 9;
            var nbColMax = 3;
            var nbCol = 1;
            var enterpriseUrl = ConfigurationManager.AppSettings["enterprisesUrl"];
            var i = 0;
            var j = 0;
            var enterprises = _enterprisesRepo.GetAll(true);
            var nbItemCol = enterprises.Count/3 > nbMaxItemCol ? nbMaxItemCol : enterprises.Count/3;
            var html = "<div id=\"companies_list_content\">\n";
            foreach (var e in enterprises)
            {
                //build my enterprise HTML
            }
            if (enterprises.Count > 0)
            {
                html += "</ul>\n</td>\n";
                html += "</tr>\n";
                html += "</tbody>\n";
                html += "</table>\n";
                html += "</div>\n";
            }
            html += "</div>\n";
            html += "<div id=\"companies-nav\"></div>";
            html += "<div class=\"companies_list_see_all\"><a href=\"" + enterpriseUrl + "\">Voir la liste complète</a></div>\n";

            return Content(html, "text/html");
        }

Is it possible to do something like this with Umbraco? Like calling a custom UserControl that connect to a DB ou to Umbraco's DB and returns the data in JSON or other javascript friendly format? How do I setup a url to do so and how do I know what is the url I can call for the data?

Thanks a lot!