<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>

<div ng-app="myApp" ng-controller="myCtrl">
{{ firstName + " " + lastName }}
</div>

<script src="myApp.js"></script>
<script src="myCtrl.js"></script>

</body>
</html>
// Code goes here

/* Styles go here */

var app = angular.module("myApp", []);
app.controller("myCtrl", function($scope) {
    $scope.firstName = "John";
    $scope.lastName= "Doe";
});
<div>
w3s104-AngularJS External JS Files
<br/>
code example:
  <hr>
  index.html
  <br/>
  <textarea 
  id='codeoutput' 
  style="width: 100%;height: 300px;background-color: #dffff4;
      font-size: 1em;font-family: Verdana, Arial, Helvetica, sans-serif;
      border: 1px solid black;">
      
<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<body>

<div ng-app="myApp" ng-controller="myCtrl">
{{ firstName + " " + lastName }}
</div>

<script src="myApp.js"></script>
<script src="myCtrl.js"></script>

</body>
</html>

  </textarea>
  <hr>
   myApp.js
  <br/>
  <textarea 
  id='codeoutput' 
  style="width: 100%;height: 300px;background-color: #dffff4;
      font-size: 1em;font-family: Verdana, Arial, Helvetica, sans-serif;
      border: 1px solid black;">
      
var app = angular.module("myApp", []);

  </textarea>



  <hr>
   myCtrl.js
  <br/>
  <textarea 
  id='codeoutput' 
  style="width: 100%;height: 300px;background-color: #dffff4;
      font-size: 1em;font-family: Verdana, Arial, Helvetica, sans-serif;
      border: 1px solid black;">
      
app.controller("myCtrl", function($scope) {
    $scope.firstName = "John";
    $scope.lastName= "Doe";
});

  </textarea>
  <hr> 
  
  
  <iframe 
  allowfullscren="allowfullscren" 
  frameborder="0" 
  src="https://embed.plnkr.co/5aP0qFi6V2DeW2ZhEig6?show=preview" 
  style="height: 400px; width: 100%;">
  </iframe>
  <hr> 
https://www.w3schools.com/angular/angular_modules.asp
  <hr> 
  201603
</div>