Read and store the click ID

When you send events yourself – from a custom booking system, an in-house form or your own backend – the click_id is what ties each event to the exact campaign, ad set and ad. This page shows where the tracking script keeps the click ID, every way to read it, and how to combine those ways so you still have the ID when one of them fails.

Where the click ID lives

When a visitor lands with lj_click_id in the URL (every tracked link carries it), the tracking script saves that ID. A visitor without one gets a new click ID from the script. So on any page where the script has run, the visitor has a click ID – and it's stored in several places at once:

Ways to read the click ID

1. The JavaScript API (recommended)

Once the script has loaded, it exposes window.lj:

const clickId = await window.lj.getClickId();

window.lj only exists after the script has loaded. If an ad blocker or consent tool stops the script, or it isn't installed on the page, window.lj is undefined – which is why the recommended setup falls back to the other ways.

2. Browser storage

You can read the stored values directly. This still works when the script is blocked on the current page view, as long as it ran on an earlier visit to the same host:

localStorage.getItem("clickId");
sessionStorage.getItem("clickId");
decodeURIComponent(document.cookie.match(/(?:^|; )clickId=([^;]*)/)?.[1] ?? "");

3. A hidden form field

Add a hidden input to your form – no JavaScript needed. The script fills it with the click ID automatically:

<input type="hidden" name="lj_click_id" />

The script recognises the names lj_click_id, lj_clickid, click_id and clickid (also with a trailing _, and as form_fields[lj_click_id] for Elementor), and inputs whose aria-label is one of those names. Fields added after page load – a later step of a multi-step form, a widget that renders late – are filled as soon as they appear. If your own code resets the value, call window.lj.mountClickId() to fill it again.

4. On your server: the clickId cookie

The browser sends the clickId cookie with every request to the same host the script runs on. If your booking form submits to that host, your server can read the ID without any JavaScript:

// with the cookie-parser middleware
const clickId = req.cookies.clickId ?? null;

$clickId = $_COOKIE['clickId'] ?? null;

click_id = request.cookies.get("clickId")

The cookie is set for the exact host only. A request from www.yourbrand.com to api.yourbrand.com does not carry it.

5. From the URL

On a page without the tracking script, the click ID arrives as ?lj_click_id=… – for example when a visitor clicks from your website to a booking system on another host. It's only in the URL of that first page, so read it once on page load and keep it:

// Only on pages WITHOUT the tracking script – run once on page load
const fromUrl = new URLSearchParams(window.location.search).get("lj_click_id");
if (fromUrl) {
  try {
    localStorage.setItem("clickId", fromUrl);
  } catch {}
}

Storing it under clickId means the helper below finds it the same way as on pages with the script. On pages with the script, don't rely on the URL: the script removes lj_click_id from the address bar as soon as it has saved the ID.

The recommended setup: combine them

No single way works everywhere – scripts get blocked, forms live on other subdomains, React forms ignore hidden fields, and bookings often reach your system days before the next event. Layer the ways so that each one covers the gaps of the others.

// Returns the visitor's LeadJourney click ID, or null if there is none.
async function getClickId() {
  try {
    const id = await window.lj?.getClickId();
    if (id) return id;
  } catch {}

  const fallbacks = [
    () => localStorage.getItem("clickId"),
    () => decodeURIComponent(document.cookie.match(/(?:^|; )clickId=([^;]*)/)?.[1] ?? ""),
    () => sessionStorage.getItem("clickId"),
    () => new URLSearchParams(window.location.search).get("lj_click_id"),
  ];
  for (const read of fallbacks) {
    try {
      const id = read();
      if (id) return id;
    } catch {}
  }
  return null;
}

<form id="booking-form" method="post" action="/bookings">
  <!-- your fields: name, email, phone, date … -->
  <input type="hidden" name="lj_click_id" />
</form>

<script>
  const form = document.getElementById("booking-form");
  form.addEventListener("submit", async (event) => {
    event.preventDefault();
    const field = form.elements.namedItem("lj_click_id");
    if (!field.value) field.value = (await getClickId()) ?? "";
    form.submit();
  });
</script>

bookingForm.addEventListener("submit", async (event) => {
  event.preventDefault();
  const data = Object.fromEntries(new FormData(bookingForm));

  await fetch("/api/bookings", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ ...data, click_id: await getClickId() }),
  });
});

const clickId =
  req.body.click_id || req.body.lj_click_id || req.cookies.clickId || null;

$clickId = null;
foreach ([$_POST['click_id'] ?? null, $_POST['lj_click_id'] ?? null, $_COOKIE['clickId'] ?? null] as $value) {
    if (!empty($value)) {
        $clickId = $value;
        break;
    }
}

click_id = (
    request.form.get("click_id")
    or request.form.get("lj_click_id")
    or request.cookies.get("clickId")
)

{
  "type": "BookedCall",
  "click_id": "8f3c2a1e-4b7d-4c1a-9e2f-6d5b3a7c9e10",
  "email": "[email protected]",
  "phone": "+491701234567",
  "first_name": "Anna",
  "last_name": "Schmidt"
}

Across domains, subdomains and iframes

Because storage belongs to one host, the click ID has to travel in the URL whenever your booking system runs somewhere else than the page the visitor landed on.

getClickId().then((clickId) => {
  if (!clickId) return;
  document.querySelectorAll('a[href^="https://yourbooking.com"]').forEach((link) => {
    const url = new URL(link.href);
    url.searchParams.set("lj_click_id", clickId);
    link.href = url.toString();
  });
});

<iframe id="booking" title="Book a call" width="100%" height="700"></iframe>

<script>
  getClickId().then((clickId) => {
    const src = new URL("https://yourbooking.com/embed");
    if (clickId) src.searchParams.set("lj_click_id", clickId);
    document.getElementById("booking").src = src.toString();
  });
</script>

Check that it works

1. Open your site through a tracked link – a test ad URL or a link from the UTM Builder.
2. Open the browser's developer tools and run in the Console:

   await window.lj.getClickId();
   window.lj.getTrackingStatus();

   Under Application → Local storage and Cookies you'll find the same ID as clickId.
3. Submit a test booking and check that the record in your system has the click ID.
4. Send the event and open the API Postbacks log to confirm it matched a click.

getTrackingStatus() returns one of these values:

FAQ

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