tag-organic-or-direct

<script>
  var OoDvalue = "";
  var hackyFix = true;

  var InternalReferral = "example.com";
  // change to name of site
    var OoDcookieName = '_OrgOrDirect';
  // cookie name
  var OoDcookieSet = 'narwhal';
  // value if set

  if (document.referrer.toLowerCase().indexOf(InternalReferral) < 0)
  {
      // clears the cookie unless the referral source is internal
      eraseCookie(OoDcookieName);
      hackyFix = false;

  }

  if (readCookie(OoDcookieName) !== null && hackyFix) {
      OoDvalue = readCookie(OoDcookieName);
    // reads the stored referral source.
  }

  if (document.referrer === "" || (document.referrer.indexOf('www.google.') > -1 && window.location.href.toLowerCase().indexOf('gclid=') < 0) || OoDvalue == OoDcookieSet) {
    // if referral is direct, from www.google but doesn't include a gclid OR the stored cookie value says they were direct/organic

    updateCookie(OoDcookieName, OoDcookieSet, 30);
    // 30 = 30 days cookie length. Increase if you want. 

    itsOrganicOrDirect();
    // fires the event. 
  }
  else {

   // its not. Nothing happens here. 


  }



  function itsOrganicOrDirect() {

   //pushes an event and no value. Left placeholder if you wanted to push some value and weren't familiar with JSON
    dataLayer.push({
      'event': 'OrganicOrDirect',
      'placeholder': 'hello'
    });

  }

  function updateCookie(name, initValue, days) {
    if (readCookie(name) !== null) {
      var value = readCookie(name);
      createCookie(name, value, days);
    } else {
      createCookie(name, initValue, days);
    }
  }

  function createCookie(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 = name + "=" + value + expires + "; path=/";
  }

  function readCookie(name) {
    var nameEQ = 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;
  }

  function eraseCookie(name) {
    createCookie(name, "", -1);
  }

  </script>