Allows me to set any query value in the pages query string then rebuild the iframe and set value for hidden fields

Unbounce + Pardot Iframe Embed

<noscript>
  <iframe src="YOUR_IFRAME_URL" scrolling="no" type="text/html" frameborder="0" allowTransparency="true" style="width:300px;height:100%;overflow:hidden;border: 0"></iframe>
</noscript>

<script type="text/javascript">
  
  // Add / Update a key-value pair in the URL query parameters
  function updateUrlParameter(uri, key, value) {
    // remove the hash part before operating on the uri
    var i = uri.indexOf('#');
    var hash = i === -1 ? ''  : uri.substr(i);
         uri = i === -1 ? uri : uri.substr(0, i);

    var re = new RegExp("([?&])" + key + "=.*?(&|$)", "i");
    var separator = uri.indexOf('?') !== -1 ? "&" : "?";
    if (uri.match(re)) {
        uri = uri.replace(re, '$1' + key + "=" + value + '$2');
    } else {
        uri = uri + separator + key + "=" + value;
    }
    return uri + hash;  // finally append the hash as well
  }
    
  function getParameterByName(name, url) {
    if (!url) url = window.location.href;
    name = name.replace(/[\[\]]/g, "\\$&");
    var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/\+/g, " "));
  }
  
  var queryString = window.location.search;
  var fullUrl = window.location.href;
  var lpVariant = 'Variant A';
  var basicUrl = [location.protocol, '//', location.host, location.pathname].join('');
  var importantInfo = basicUrl + ' ' + lpVariant;
  
  var updatedUrl = updateUrlParameter(fullUrl, 'source', importantInfo);
  
  window.history.replaceState( {} , 'source', updatedUrl);

  var utm_source = getParameterByName('utm_source');
  var utm_medium = getParameterByName('utm_medium');
  var utm_campaign = getParameterByName('utm_campaign');
  var utm_term = getParameterByName('utm_term');
  var source = getParameterByName('source');
  
  var utmFields = 'utm_source:' + utm_source + ', utm_medium:' + utm_medium + ', utm_campaign:' + utm_campaign + ', utm_term:' + utm_term;
  
  var finalUrl = updateUrlParameter(updatedUrl, 'query', utmFields);
  
  console.log(utmFields);
   
  window.history.replaceState( {} , 'query', finalUrl);
  
  //Begin rebuilding iframe
  
  var form = 'YOUR_IFRAME_URL';
  var params = window.location.search;
  var thisScript = document.scripts[document.scripts.length - 1];
  var iframe = document.createElement('iframe');

 iframe.setAttribute('src', form + params);
 iframe.setAttribute('width', '270px');
 iframe.setAttribute('height', '100%');
 iframe.setAttribute('type', 'text/html');
 iframe.setAttribute('frameborder', 0);
 iframe.setAttribute('allowTransparency', 'true');
 iframe.setAttribute('scrolling', 'no');
 iframe.style.border = '0';

 thisScript.parentElement.replaceChild(iframe, thisScript);
  
</script>