AngularJS submit form to db via php - angularjs

Question

i'm approching angularJS and i'd like to submit a form to db via php.
i tried this but it does not work.
any help?
i get an error when i click the submit button.
thanks.
//index.html
angular.module("myApp")
.controller("addUtentiCtrl", function($scope, $http) {
$scope.utenteForm = {};
$scope.submit = function() {
$http({
method : 'POST',
url : 'backInsertUtenti',
data : param($scope.utenteForm),
headers : { 'Content-Type': 'application/x-www-form-urlencoded' }
})
.success(function() {
alert("Dati inseriti correttamente!");
})
.error(function() {
alert("Errore inserimento dati!");
});
};
});
//aggiungiUtente.html
<form ng-submit="submit()" ng-controller="addUtentiCtrl" novalidate>
<input type="text" ng-model="utenteForm.nome" name="nome" ng-maxlength="10" ng-required="true">
<input type="text" ng-model="utenteForm.cognome" name="cognome" ng-maxlength="10" ng-required="true">
<input type="text" ng-model="utenteForm.citta" name="citta" ng-maxlength="10" ng-required="true">
<input ng-enable="utenteForm.$valid" type="submit" id="submit" value="Submit" />
</form>
//backInsertUtenti.php
<?php
//define of variable for the connection
$db= new mysqli($host,$username,$password,$db_name);
$sql=$db->prepare("INSERT INTO utenti (id, nome, cognome, citta) VALUES (0, ?, ?, ?)");
$sql->bind_param('sss',$_POST['nome'],$_POST['cognome'],$_POST['citta']);
$sql->execute();
?>