intl-tel-input
The preferred way to install this extension is through composer.
Either run
php composer.phar require --prefer-dist avikarsha/yii2-intl-tel-input "*"
or add
"avikarsha/yii2-intl-tel-input": "*"
to the require section of your composer.json file.
Once the extension is installed, simply use it in your code by :
<?= \avikarsha\intltelinput\IntlTelInput::widget(); ?>
<?= $form->field($model_user, 'attribute')
->widget(IntlTelInput::className(), []) ?>```
Client side validation added.