(function() {
  // Function to get query parameters from URL
  function getQueryParams() {
    var params = {};
    var queryString = window.location.search.substring(1);
    var regex = /([^&=]+)=([^&]*)/g;
    var m;

    while (m = regex.exec(queryString)) {
      params[decodeURIComponent(m[1])] = decodeURIComponent(m[2]);
    }

    return params;
  }

  // Function to populate hidden fields
  function populateUTMFields(params) {
    if (params.utm_source) {
      document.querySelector('input[name="utm_source"]').value = params.utm_source;
    }
    if (params.utm_medium) {
      document.querySelector('input[name="utm_medium"]').value = params.utm_medium;
    }
    if (params.utm_campaign) {
      document.querySelector('input[name="utm_campaign"]').value = params.utm_campaign;
    }
  }

  // Execute on page load
  document.addEventListener("DOMContentLoaded", function() {
    var params = getQueryParams();
    populateUTMFields(params);
  });
})();