Yii2 compare date in model with function - validation

Question

I have model with below rules
public function rules()
{
return [
['student_dob',
function ($attr) {
$curr_date = date('d-m-Y');
if(empty($this->student_adm_date)) {
//$this->addError('student_dob',"Select Admission date first");
return true;
}
else {
$dob = date('Y-m-d',strtotime($this->$attr));
$adm = date('Y-m-d',strtotime($this->student_adm_date));
$diff = $adm-$dob;
if($diff <= 14) {
$this->addError('student_dob', "Birth date must be less than Admission date.");
return false;
}
else
return true;
}
},
]
];
}
This rule works good but error message don't appear on view page and my form view is below
<?php $form = ActiveForm::begin([
'layout' => 'horizontal',
'fieldConfig' => [
'template' => "{label}\n{beginWrapper}\n{input}\n{error}\n{endWrapper}",
'horizontalCssClasses' => [
'label' => 'col-sm-4',
'offset' => 'col-sm-offset-4',
'wrapper' => 'col-sm-8',
'error' => '',
'hint' => '',
],
],
]);
?>
<div class="row-left">
<?= $form->field($info, 'student_dob', ['template' => "{label} {input} <span class='status'> </span> {error}"])->widget(yii\jui\DatePicker::className(),
[
'model'=>$info,
'attribute'=>'student_dob',
'value'=>'',
'clientOptions' =>[
'dateFormat' => 'dd-mm-yyyy',
'changeMonth'=> true,
'changeYear'=> true,
'autoSize'=>true,
'showOn'=> "button",
'yearRange'=>'1900:'.(date('Y')+1),
'buttonImage'=> Yii::$app->homeUrl."images/calendar.png",
'htmlOptions'=>[
'style'=>'width:250px;',
'class'=>'form-control',
]]]); ?>
</div>
<?php ActiveForm::end(); ?>
I want to compare student_dob and student_adm_date with student_dob < student_adm_date rule validation, also error appear on form view page.
Solution
Just remove horizontalCssClasses and change template value like,
<?php $form = ActiveForm::begin([
'layout' => 'horizontal',
'fieldConfig' => [
'template' => "{label}\n{input}\n{error}",
],
]);
?>

Answer 1

You are subtracting one sting from another, I am not sure that works
$diff = $adm - $dob;
Try
if(strtotime($this->$attr) <= strtotime($this->student_adm_date))
Or change it to calcualte 14 days... altough not sure what you can register somebody 14 days after their birth.
You can calculate
if(strtotime($this->$attr) - strtotime($this->student_adm_date) > 60 * 60 * 24 * 14)
One more thing, in the validation functions you do not need return false; or return true; Try removing these, I personally do not know if they do anything.