yii.activeform.js generate invalid validation js script - yii

Question

in a ok project，it should like this:
<script type="text/javascript">
jQuery(document).ready(function() {
jQuery('#form-signup').yiiActiveForm({
"username": {
"validate": function(attribute, value, messages) {
yii.validation.required(value, messages, {
"message": "Username\u4e0d\u80fd\u4e3a\u7a7a\u3002"
});
yii.validation.string(value, messages, {
"message": "Username\u5fc5\u987b\u662f\u4e00\u6761\u5b57\u7b26\u4e32\u3002",
"min": 2,
"tooShort": "Username\u5e94\u8be5\u5305\u542b\u81f3\u5c112\u4e2a\u5b57\u7b26\u3002",
"max": 255,
"tooLong": "Username\u53ea\u80fd\u5305\u542b\u81f3\u591a255\u4e2a\u5b57\u7b26\u3002",
"skipOnEmpty": 1
});
},
"id": "signupform-username",
"name": "username",
"validateOnChange": true,
"validateOnType": false,
"validationDelay": 200,
"container": ".field-signupform-username",
"input": "#signupform-username",
"error": ".help-block"
},
</script>
but in my project,when i enter email or username that is invalid,no hints or error shows! when i check the code generated by yii,i see null args of yiiActiveForm
<script type="text/javascript">
jQuery(document).ready(function() {
jQuery('#form-signup').yiiActiveForm([], []);
});
</script>
who can tell me why? IS there anything wrong with the vendor folder?

Answer 1

This might be because your model class is not set up to be in the right scenario, causing validation to be skipped. Please check the documentation on this topic:
http://www.yiiframework.com/doc-2.0/guide-structure-models.html#scenarios
If you want certain rules to be applied on the current view, you need to set the scenario when you create the instance of your model :
// scenario is set as a property
$model = new User;
$model->scenario = 'login';
// scenario is set through configuration
$model = new User(['scenario' => 'login']);
In your model, the case above User, you would have this function:
namespace app\models;
use yii\db\ActiveRecord;
class User extends ActiveRecord
{
public function scenarios()
{
return [
'login' => ['username', 'password'],
//more scenarios would follow here...
];
}
}