Mixpanel Last Touch UTM tracking

mixpanel-last-touch-UTM.js

function getQueryParam(url, param) {
  // Expects a raw URL
  param = param.replace(/[[]/, "\[").replace(/[]]/, "\]");
  var regexS = "[\?&]" + param + "=([^&#]*)",
    regex = new RegExp(regexS),
    results = regex.exec(url);
  if (results === null || (results && typeof(results[1]) !== 'string' && results[1].length)) {
    return '';
  } else {
    return decodeURIComponent(results[1]).replace(/\W/gi, ' ');
  }
};


function campaignParams() {
  var campaign_keywords = 'utm_source utm_medium utm_campaign utm_content utm_term'.split(' '),
    kw = '',
    params = {},
    first_params = {};

  var index;
  for (index = 0; index < campaign_keywords.length; ++index) {
    kw = getQueryParam(document.URL, campaign_keywords[index]);
    if (kw.length) {
      params[campaign_keywords[index] + ' [last touch]'] = kw;
    }
  }
  for (index = 0; index < campaign_keywords.length; ++index) {
    kw = getQueryParam(document.URL, campaign_keywords[index]);
    if (kw.length) {
      first_params[campaign_keywords[index] + ' [first touch]'] = kw;
    }
  }

  mixpanel.people.set(params);
  mixpanel.people.set_once(first_params);
  mixpanel.register(params);
}

campaignParams();