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<body ng-app='MainApp'>
    <div ng-controller='MainCtrl'>
      <b>Start Typing</b>
        <p>{{updated}}</p>
        <input type='text' ng-model='text'/>
        <button ng-click='stop();'>Stop</button>
      
    </div>
</body>
var mainMod = angular.module('MainApp', []);

mainMod.controller('MainCtrl', function ($scope) {
    $scope.updated = 0;
    var watcher = $scope.$watch('text',function(newVal,oldVal){
        $scope.updated++;
    });
    $scope.stop = function(){
       watcher();
      alert('stop');
    };
});
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