To Retrieve Logged In User CRM Role

Below is the code snippet which will bring the current logged in user crm role.

var has_role = UserHasRole('Sales Representative');
function UserHasRole(roleName) {
            var serverUrl = "/" + Xrm.Page.context.getOrgUniqueName();
            var oDataEndpointUrl = serverUrl + "/XRMServices/2011/OrganizationData.svc/";
            oDataEndpointUrl += "RoleSet?$top=1&$filter=Name eq '" + roleName + "'";
            var service = GetRequestObject();
            if (service != null) {
                service.open("GET", oDataEndpointUrl, false);
                service.setRequestHeader("X-Requested-Width", "XMLHttpRequest");
                service.setRequestHeader("Accept", "application/json, text/javascript, */*");
                service.send(null);
                var requestResults = eval('(' + service.responseText + ')').d;
                if (requestResults != null && requestResults.length == 1) {
                    var role = requestResults[0];
                    var id = role.RoleId;
                    var currentUserRoles = Xrm.Page.context.getUserRoles();
                    for (var i = 0; i < currentUserRoles.length; i++) {
                        var userRole = currentUserRoles[i];
                        if (GuidsAreEqual(userRole, id)) {
                            return true;
                        }
                    }
                }
            }
            return false;
        }
        function GetRequestObject() {
            if (window.XMLHttpRequest) {
                return new window.XMLHttpRequest;
            }
            else {
                try {
                    return new ActiveXObject("MSXML2.XMLHTTP.3.0");
                }
                catch (ex) {
                    return null;
                }
            }
        }
        function GuidsAreEqual(guid1, guid2) {
            var isEqual = false;
            if (guid1 == null || guid2 == null) {
                isEqual = false;
            }
            else {
                isEqual = guid1.replace(/[{}]/g, "").toLowerCase() == guid2.replace(/[{}]/g, "").toLowerCase();
            }
            return isEqual;
        }