Проверьте значение текстового блока на значение ng-change == в угловой
<script>
angular.module('changeExample', [])
.controller('ExampleController', ['$scope', function($scope) {
$scope.evaluateChange = function(obj,$event) {
var currentElement = $event.target;
console.log(currentElement.value);//this will give you value of current element
};
}]);
</script>
<div ng-controller="ExampleController">
<textarea ng-change="evaluateChange(this)" id="ng-change-example1"></textarea>
</div>
Ankur