AngularJS Live Example

HTML

<script src="http://underscorejs.org/underscore-min.js"></script>
<div ng-controller = "fessCntrl"> 
  
<input type="text" ng-model="data.name" value=""/>
{{data.count}}
</div>

JavaScript

var app = angular.module('myModule', []);

app.controller('fessCntrl', function ($scope) {
    
    $scope.data = {
        name:"tom",
        count: 0
    };

    $scope.$watch('data', function(oldValue,newValue) {
         if(oldValue.name != newValue.name){
             ++$scope.data.count;
          }

    },true);
    
});