Gravity Forms - Fill in hidden fields with data from URL Query Parameters such as UTM_*

gf_query2hidden.js

/**
 * This function parses the URL for a given parameter and returns the value of that parameter
 */
function getUrlParameter(name) {
  name = name.replace(/[\[]/, '\\[').replace(/[\]]/, '\\]');
  var regex = new RegExp('[\\?&]' + name + '=([^&#]*)');
  var results = regex.exec(location.search);

  return results === null ? '' : decodeURIComponent(results[1].replace(/\+/g, ' '));
}

/**
 * Enter all the parameters you want to capture from the URL into the array.
 */
var urlParamsToForward = [
  'email',
  'utm_medium',
  'utm_campaign',
  'utm_content',
  'utm_source'
];

/**
 * Loop through the array of query parameters you want, Save the results into a hidden field with a VALUE that matches
 * the name of the parameter. This should be setup properly in GravityForms.
 */
jQuery.each(urlParamsToForward, function(i, param) {
  var selector = 'input[value="' + param + '"]';
  jQuery(selector).val(getUrlParameter(param));
});