Angularjs How to get value of input[text] in controller - angularjs

Question

I want to get value of input[text] in my controller when data is changed as this source code:
(function () {
'use strict';
var app = angular.module('app', ['ngMaterial']);
app.controller('ScanDataCtrl', function ($scope) {
$scope.getScannedData = function () {
console.log($scope.formScanData.scanDataIReceipt);
};
});
app.directive('scanDataBScan', function ($mdDialog, $sce, $http) {
return {
restrict: 'C',
link: function (scope, element, attrs) {
element.on('click', function () {
scope.getScannedData();
// => the value always undefined
});
}
};
});
});
<div ng-controller="ScanDataCtrl">
<form accept-charset="UTF-8" class="form-inline formScanData" name="formScanData">
<input ng-model="formScanData.scanDataIReceipt" type="text" required>
<md-input-container>
<md-button ng-model="scanDataBScan" class="md-raised md-primary scanDataBScan">Scan</md-button>
</md-input-container>
</form>
</div>
the result of this source code is always undefine
Please help me.
If I ask wrong or bad with my English, I am sorry.
Thank you!

Answer 1

Use the ng-change directive:
<input ng-model="formScanData.scanDataIReceipt" type="text"
ng-change="getScannedData()" required>
For more information, see AngularJS ng-change Directive API Reference.

Answer 2

(function () {
'use strict';
var app = angular.module('app', ['ngMaterial']);
app.controller('ScanDataCtrl', function ($scope) {
$scope.getScannedData = function (data) {
console.log(data);
};
});
app.directive('scanDataBScan', function ($mdDialog, $sce, $http) {
return {
restrict: 'C',
link: function (scope, element, attrs) {
element.on('click', function () {
scope.getScannedData();
// => the value always undefined
});
}
};
});
});
<div ng-controller="ScanDataCtrl">
<form accept-charset="UTF-8" class="form-inline formScanData" name="formScanData">
<input ng-model="formScanData.scanDataIReceipt" type="text" required>
<md-input-container>
<md-button ng-model="scanDataBScan" ng-click="getScannedData(formScanData.scanDataIReceipt)" class="md-raised md-primary scanDataBScan">Scan</md-button>
</md-input-container>
</form>
</div>