You must to use events to get selected date to get day name.
I used changeDate
event,
here is code:
<?= $form->field($model, 'appDate')->widget(
DatePicker::className(), [
'inline' => false,
'clientOptions' => [
'autoclose' => true,
'format' => 'yyyy-m-d',
],
'clientEvents' => [
'changeDate' => new \yii\web\JsExpression('function(e){var days =["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"];
$("#dayname").text(days[e.date.getDay()]); }') ,
] ,
]);?>
I created an element for showing day name:
<span id="dayname"></span>
For put into your input:
<?= $form->field($model, 'appDate')->widget(
DatePicker::className(), [
'inline' => false,
'clientOptions' => [
'autoclose' => true,
'format' => 'yyyy-m-d',
],
'clientEvents' => [
'changeDate' => new \yii\web\JsExpression('function(e){var days =["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday","Sunday"];
$("#appointment-appday").val(days[e.date.getDay()]); }') ,
] ,
]);?>