Uncaught ReferenceError: angular is not defined -

2019-01-13 23:57发布

站内文章 / JavaScript
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问题:

I'm attempting to learn angular and I am struggling with a simple button click.
I followed an example which has an identical code to the one below.

The result I am looking for is for the button click to cause an alert. However, there is no response to the button click. Does anybody have any ideas? 

<html lang="en" ng-app="myApp" >
<head>
  <meta charset="utf-8">
  <title>My AngularJS App</title>
  <link rel="stylesheet" href="css/app.css"/>
</head>
<body>
    <div >
        <button my-directive>Click Me!</button>
    </div>

    <script>
        var app = angular.module('myApp',[]);

        app.directive('myDirective',function(){

            return function(scope, element,attrs) {
                element.bind('click',function() {alert('click')});
            };

        });
    </script>

    <h1>{{2+3}}</h1>

  <!-- In production use:
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
  -->
  <script src="lib/angular/angular.js"></script>
  <script src="lib/angular/angular-route.js"></script>
  <script src="js/app.js"></script>
  <script src="js/services.js"></script>
  <script src="js/controllers.js"></script>
  <script src="js/filters.js"></script>
  <script src="js/directives.js"></script>
</body>
</html>

回答1:

You need to move your angular app code below the inclusion of the angular libraries. At the time your angular code runs, angular does not exist yet. This is an error (see your dev tools console).

In this line:

var app = angular.module(`

you are attempting to access a variable called angular. Consider what causes that variable to exist. That is found in the angular.js script which must then be included first.

  <h1>{{2+3}}</h1>

  <!-- In production use:
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
  -->
  <script src="lib/angular/angular.js"></script>
  <script src="lib/angular/angular-route.js"></script>
  <script src="js/app.js"></script>
  <script src="js/services.js"></script>
  <script src="js/controllers.js"></script>
  <script src="js/filters.js"></script>
  <script src="js/directives.js"></script>

      <script>
        var app = angular.module('myApp',[]);

        app.directive('myDirective',function(){

            return function(scope, element,attrs) {
                element.bind('click',function() {alert('click')});
            };

        });
    </script>

For completeness, it is true that your directive is similar to the already existing directive ng-click, but I believe the point of this exercise is just to practice writing simple directives, so that makes sense.



回答2:

Use the ng-click directive:

<button my-directive ng-click="alertFn()">Click Me!</button>

// In <script>:
app.directive('myDirective' function() {
  return function(scope, element, attrs) {
    scope.alertFn = function() { alert('click'); };
  };
};

Note that you don't need my-directive in this example, you just need something to bind alertFn on the current scope.

Update: You also want the angular libraries loaded before your <script> block.



回答3:

Just to complement m59's correct answer, here is a working jsfiddle:

<body ng-app='myApp'>
    <div>
        <button my-directive>Click Me!</button>
    </div>
     <h1>{{2+3}}</h1>

</body>


回答4:

As you know angular.module( declared under angular.js file.So before accessing angular.module, you must have make it available by using <script src="lib/angular/angular.js"></script>(In your case) after then you can call angular.module. It will work.

like

<html lang="en">
<head>
  <meta charset="utf-8">
  <title>My AngularJS App</title>
  <link rel="stylesheet" href="css/app.css"/>
<!-- In production use:
  <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
  -->
  <script src="lib/angular/angular.js"></script>
  <script src="lib/angular/angular-route.js"></script>
  <script src="js/app.js"></script>
  <script src="js/services.js"></script>
  <script src="js/controllers.js"></script>
  <script src="js/filters.js"></script>
  <script src="js/directives.js"></script>

    <script>
        var app = angular.module('myApp',[]);

        app.directive('myDirective',function(){

            return function(scope, element,attrs) {
                element.bind('click',function() {alert('click')});
            };

        });
    </script>
</head>
<body ng-app="myApp">
    <div >
        <button my-directive>Click Me!</button>
    </div>
    <h1>{{2+3}}</h1>

</body>
</html>


回答5:

i forgot to add below line to my HTML code after i add problem has resolved.

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.6/angular.js"></script>


标签： javascript angularjs button angularjs-directive
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