function getParameterByName(name) { name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]"); var regex = new RegExp("[\\?&]" + name + "=([^]*)"); var results = regex.exec(location.search); return results == null ? "" : decodeURIComponent(results[1].replace(/\+/g, " ")); } $preview = getParameterByName("preview");

if( $preview == "" ){ // do nothing } else if( $preview == "control" ){ document.cookie = "lander-ab-tests-21836780=lander_control"; } else{ document.cookie = "lander-ab-tests-21836780=lander_" + $preview; }