https://firmafaro.pl/wp-content/plugins/woo-payu-payment-gateway/assets/js/sf-init.js?ver=2.9.0

1function sf_init() {
2  var cc = document.getElementById( 'payu-card-container' );
3  if ( cc ) {
4    var lang = cc.dataset.lang;
5    var optionsForms = {
6      cardIcon: true,
7      style: {
8        basic: {
9          fontSize: '18px',
10        },
11      },
12      placeholder: {
13        number: '',
14        date: 'MM/YY',
15        cvv: '',
16      },
17      lang: lang,
18    };
19    var pcn = document.getElementById( 'payu-card-number' );
20    if ( pcn.childNodes.length === 0 ) {
21      var payuSdkForms = PayU( cc.dataset.payuPosid );
22      var secureForms = payuSdkForms.secureForms();
23      var cardNumber = secureForms.add( 'number', optionsForms );
24      var cardDate = secureForms.add( 'date', optionsForms );
25      var cardCvv = secureForms.add( 'cvv', optionsForms );
26
27      cardNumber.render( '#payu-card-number' );
28      cardNumber.on( 'change', function ( ev ) {
29        if ( ev.empty === false && ev.error === false && ev.length === 16 ) {
30          cardDate.focus();
31        }
32      } );
33
34      cardDate.render( '#payu-card-date' );
35      cardDate.on( 'change', function ( ev ) {
36        if ( ev.empty === false && ev.error === false ) {
37          cardCvv.focus();
38        }
39      } );
40
41      cardCvv.render( '#payu-card-cvv' );
42      window.payuSdkForms = payuSdkForms;
43    }
44  }
45}