UTM_Mautic_Tracking.js

function getParameterByName(name) {
    var 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, " "));
}

$( "input[name*='mauticform'][type='hidden']" ).each(function(index){
  var itemName = $(this).attr('name').match(/\[(.*?)\]/)[1];
  var utms = ["gclid", "utm_source", "utm_medium", "utm_campaign", "utm_content", "utm_term"];
  if($.inArray(itemName, utms) !== -1){
  var elementName = "input[name='mauticform["+ itemName +"]]";
  $(elementName).val(getParameterByName(itemName))
  }
});