Autofill with Cookie Value

I'm not Sanford, but maybe you'll find this JS useful. Just don't forget to update domain name.

This script saves UTM parameters in cookies whenever there are any UTM parameters in the URL. It also saves the initial referrer information in a cookie which is ever (365 days) overwritten.  The values in the cookies can be read and added to forms or stored in the backend database, etc.

var utmCookie = {

  cookieNamePrefix: "",

  utmParams: [

  "utm_source",

  "utm_medium",

  "utm_campaign",

  "utm_term",

  "utm_content"

  ],

  cookieExpiryDays: 365,

  // From quirksmode.org/js/cookies.html

  createCookie: function (name, value, days) {

  if (days) {

  var date = new Date();

  date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));

  var expires = "; expires=" + date.toGMTString();

  } else

  var expires = "";

  document.cookie = this.cookieNamePrefix + name + "=" + value + expires + "; domain=.abilitynetwork.com; path=/";

  },

  readCookie: function (name) {

  var nameEQ = this.cookieNamePrefix + name + "=";

  var ca = document.cookie.split(';');

  for (var i = 0; i < ca.length; i++) {

  var c = ca[i];

  while (c.charAt(0) == ' ')

  c = c.substring(1, c.length);

  if (c.indexOf(nameEQ) == 0)

  return c.substring(nameEQ.length, c.length);

  }

  return null;

  },

  eraseCookie: function (name) {

  this.createCookie(name, "", -1);

  },

  getParameterByName: function (name) {

  name = name.replace(/[\[]/, "\\\[").replace(/[\]]/, "\\\]");

  console.log(name);

  var regexS = "[\\?&]" + name + "=([^&#]*)";

  var regex = new RegExp(regexS);

  var results = regex.exec(window.location.search);

  if (results == null) {

  return "";

  } else {

  return decodeURIComponent(results[1].replace(/\+/g, " "));

  }

  },

  utmPresentInUrl: function () {

  var present = false;

  for (var i = 0; i < this.utmParams.length; i++) {

  var param = this.utmParams[i];

  var value = this.getParameterByName(param);

  console.log(param + ' = ' + value);

  if (value != "" && value != undefined) {

  present = true;

  }

  }

  return present;

  },

  writeUtmCookieFromParams: function () {

  for (var i = 0; i < this.utmParams.length; i++) {

  var param = this.utmParams[i];

  var value = this.getParameterByName(param);

  this.writeCookieOnce(param, value)

  }

  },

  writeCookieOnce: function (name, value) {

  var existingValue = this.readCookie(name);

  if (!existingValue) {

  this.createCookie(name, value, this.cookieExpiryDays);

  }

  },

  writeReferrerOnce: function () {

  value = document.referrer;

  if (value === "" || value === undefined) {

  this.writeCookieOnce("referrer", "direct");

  } else {

  this.writeCookieOnce("referrer", value);

  }

  },

  referrer: function () {

  return this.readCookie("referrer");

  }

};

utmCookie.writeReferrerOnce();

if (utmCookie.utmPresentInUrl()) {

  utmCookie.writeUtmCookieFromParams();

}