angularjs - Detect a change to a paticular element of a model in angular JS -

i want if users edit membership number or role pushes save particular row gets post requested api,

http://plnkr.co/edit/plm45ulwl2zklfdpskpl?p=preview

<tr ng-repeat="user in users" id="{{ user.userid}}">     ..     <td>{{ user.name}}</td>     <td>{{ user.email}}</td>     <td ng-click="editmemno = !editmemno" ng-show="editmemno">        {{ user.role}}       </td>     ..    <button> save</button>  .. </tr>  angular.module("userlist", []).controller("usersctrl", function($scope) {    var original = [{     "userid": "1",     "memno": "1",     "name": "asdf",     "username": "max",     "email": "max@gmail.com",     "role": "10",     "mobile": "079951334"   },    ..    }];    $scope.users = angular.copy(original);   $scope.original = angular.copy(original);    $scope.editmemno = false;    $scope.editmemno = function() {     $scope.editmemno = true;   };    $scope.roles = ["1", "2", "9", "10"]; 

basically want add ng-click button, when click it post row, database on condition has been altered (i.e. dirty state). add function, like

$scope.submitrow = function( row want  ){       $http.post bla bla  }; 

and in button have

 <button ng-click="sumbitrow(what put here?)" 

so think question stick in submitrow parameters ng-click? , or best way want achieve?

you use $scope.$watch, allows observe 1 particular property of object , bind callback event.

http://fdietz.github.io/recipes-with-angular-js/controllers/responding-to-scope-changes.html

edit: read question again. it's still bit unclear you're asking for, differences in objects try this: https://github.com/flitbit/diff