attribution-2.js

// source: https://jennamolby.com/how-to-use-cookies-to-capture-url-parameters/
(function(){
            function getCookie(cname) {
                var name = cname + "=";
                var decodedCookie = decodeURIComponent(document.cookie);
                var ca = decodedCookie.split(';');
                for(var i = 0; i <ca.length; i++) {
                    var c = ca[i];
                    while (c.charAt(0) == ' ') {
                        c = c.substring(1);
                    }
                    if (c.indexOf(name) == 0) {
                        return c.substring(name.length, c.length);
                    }
                }
                return "";
            }
            let referrer = getCookie("referrer");
            let utm_campaign = getCookie("utm_campaign");
            let utm_medium = getCookie("utm_medium");
            let utm_source = getCookie("utm_source");
            let utm_term = getCookie("utm_term");
            let utm_journey = getCookie("utm_journey");

            document.getElementById("referrer").value = referrer || "";
            document.getElementById("utm_campaign").value = utm_campaign || "";
            document.getElementById("utm_medium").value = utm_medium || "";
            document.getElementById("utm_source").value = utm_source || "";
            document.getElementById("utm_term").value = utm_term || "";
            document.getElementById("utm_journey").value = utm_journey || "";
})()