Google Chart with AngularJS

HTML

<script src="https://www.google.com/jsapi"></script>
<div ng-controller="MainController">
  <input ng-click="toggleCol()" type="checkbox" value="1" checked /><label for="chk-0">Series 0</label>
  <input ng-click="toggleCol()" type="checkbox" value="2" checked /><label for="chk-1">Series 1</label>
  <input ng-click="toggleCol()" type="checkbox" value="3" checked /><label for="chk-2">Series 2</label>

<div id="chart_div" style="width: 550px; height:330px;"></div>
</div>

JavaScript

google.load('visualization', '1', {packages:['corechart']});

var app = angular.module('myApp', []);
app.controller('MainController', function($scope) {
  $scope.datax = [
    ['Time', 'R1', 'R2', 'R3'],
    ['03-01-2017', 50, 35, 10],
    ['01-02-2017',  60, 37, 20],
    ['10-02-2017',  15, 12, 40],
    ['13-02-2017',  76, 78, 50],
    ['15-02-2017',  90, 70, 30],
    ['17-02-2017',  90, 58, 30],
    ['20-02-2017',  90, 40, 60]
  ];

  var options = {
    title: 'mobile Releases',
    legend: {
      position: 'none'
    },
    vAxis:{
      title: 'MS',
      titleTextStyle: {
        color: '#FF0000'
      },
      maxValue: 100,
      minValue: 0,
      gridlines: {
        count: 10
      }
    },
    hAxis:{
      gridlines:{
        count: 10
      }
    },
    curveType: 'function',
    explorer: {},
    pointSize: 5,
    interpolateNulls: true
  };

  var chart = new google.visualization.LineChart(document.getElementById('chart_div'));
  var formatPercent = new google.visualization.NumberFormat({
    fractionDigits: 0,
    suffix: 'ms'
  });
  var formatTime = new google.visualization.PatternFormat('{0} Uhr');

  var data;
  var colors = ['red', 'blue', 'green'];
  $scope.$watch('datax', function(newValue, oldValue) {
    data = google.visualization.arrayToDataTable($scope.datax);
  	colors.forEach(function (color, index) {
    	data.setColumnProperty(index + 1, 'color', color);
  	});
		drawChart();
  }, true);

  $scope.toggleCol = function() {
    drawChart();
  }

  function drawChart() {
    var chartColors = [];
    var chartColumns = [0];
    var view = new google.visualization.DataView(data);

    var checks = document.getElementsByTagName('input');
    for (var i = 0; i < checks.length; i++) {
      var seriesColumn = parseInt(checks[i].value);
      if (checks[i].checked) {
        chartColumns.push(seriesColumn);
        chartColors.push(data.getColumnProperty(seriesColumn, 'color'));
      }
    }
    view.setColumns(chartColumns);
   ...