When internal promotion (banner) is displayed

<script>
var dataLayer  = window.dataLayer || [];
dataLayer.push({
  'ecommerce': {
    'promoView': {
      'promotions': [
       {
         'id': 'Slider-Home1',        //name or id required
         'name': 'June Sale',       //name or id required
         'creative': 'banner1',
         'position': 'first'       },
       {
         'id': 'Slider-Home2',
         'name': 'July Sale',
         'creative': 'banner1',
         'position': 'last'       }]
    }
  }
});
</script>