Class change Observer with MutationObserver read more at https://developer.mozilla.org/pt-BR/docs/Web/API/MutationObserver

observer.js

/// read more at
var $div = $(".card");
var observer = new MutationObserver(function(mutations) {
  mutations.forEach(function(mutation) {
    if (mutation.attributeName === "class") {
      var attributeValue = $(mutation.target).prop(mutation.attributeName);
      console.log("Class attribute changed to:", attributeValue);
      console.log($(mutation.target));
      $( document ).trigger( "validateCard", attributeValue );
    }
  });
});
observer.observe($div[0], {
  attributes: true
});

$( document ).on( "validateCard", {
    button: "allow"
}, function( event, card ) {
    console.log( event.data.foo ); // "bar"
    console.log( card );           // "bim"
});
 
$( document ).trigger( "validateCard", [ "bim", "baz" ] );