function getParameterByName(name, url = window.location.href) {
name = name.replace(/[\[\]]/g, '\\amp;');
var regex = new RegExp('[?&]' + name + '(=([^&#]*)|&|#|$)'),
results = regex.exec(url);
if (!results) return null;
if (!results[2]) return '';
return decodeURIComponent(results[2].replace(/\+/g, ' '));
var utms = ['utm_source', 'utm_medium', 'utm_campaign'];
utms.forEach(function(utm) {
utm && UST.addTag(utm + ':' + getParameterByName(utm));