Squarespace

<script src="https://attr.boggsmtk.com/v1/tag.js?k=YOUR_LICENSE_KEY"></script>

<!-- MTK Attribution Squarespace Companion Script -->
  <script>
  (function () {
    // Values to keep OUT. Both of these are long enough to crowd a URL past
    // its ceiling on their own, and everything inside them already rides
    // along in the individual fields. Add any field you don't want on the
    // platform — each one you drop frees room for the rest.
    var EXCLUDE = [
      'mtk_journey_json',
      'mtk_attribution_summary'
    ];

    // Only when the platform's key has to differ from the field name.
    var RENAME = {
      // 'mtk_first_channel': 'first_channel'
    };

    // The tag also publishes each value under its retired spelling so older
    // client forms keep filling. That is for forms, not for us — carrying both
    // would double the payload for nothing.
    var LEGACY_PREFIXES = ['mtk_ft_', 'mtk_lt_'];
    var LEGACY_NAMES = [
      'mtk_time_since_paid',
      'mtk_conversion_timestamp',
      'mtk_summary',
      'mtk_touch_path',
      'mtk_touch_path_json'
    ];

    // Titles the generic rule can't produce (click IDs stay lowercase).
    var TITLE_EXCEPTIONS = {"mtk_gclid":"gclid","mtk_gbraid":"gbraid","mtk_wbraid":"wbraid","mtk_msclkid":"msclkid","mtk_page_url":"Page URL","mtk_fbclid":"fbclid","mtk_fbc":"fbc","mtk_fbp":"fbp"};

    function isLegacy(key) {
      for (var i = 0; i < LEGACY_PREFIXES.length; i++) {
        if (key.indexOf(LEGACY_PREFIXES[i]) === 0) return true;
      }
      return LEGACY_NAMES.indexOf(key) > -1;
    }

    // 'mtk_first_channel' -> 'First Channel', matching the Field Name the
    // dashboard shows for that row.
    function titleOf(key) {
      if (TITLE_EXCEPTIONS[key]) return TITLE_EXCEPTIONS[key];
      var words = key.replace(/^mtk_/, '').split('_');
      var out = [];
      for (var i = 0; i < words.length; i++) {
        if (!words[i]) continue;
        out.push(
          words[i] === 'json'
            ? 'JSON'
            : words[i].charAt(0).toUpperCase() + words[i].slice(1)
        );
      }
      return out.join(' ');
    }

    // Order values are added in, which on a length-capped platform is also
    // drop priority: what a lead is worth least without goes last. Anything
    // not listed (a custom field, a new default) sorts after these, so a drop
    // is predictable rather than whatever order the event happened to be in.
    var PRIORITY = [
      'mtk_last_channel', 'mtk_last_source', 'mtk_last_medium', 'mtk_last_campaign',
      'mtk_gclid', 'mtk_gbraid', 'mtk_wbraid', 'mtk_msclkid',
      'mtk_first_channel', 'mtk_first_source', 'mtk_first_medium', 'mtk_first_campaign',
      'mtk_page_path', 'mtk_page_url',
      'mtk_conversion_unix', 'mtk_conversion_datetime', 'mtk_custom_conversion_time',
      'mtk_fbclid', 'mtk_fbc', 'mtk_fbp',
      'mtk_last_landing_page', 'mtk_last_landing_page_group', 'mtk_first_landing_page',
      'mtk_session_count', 'mtk_pageview_count', 'mtk_paid_touch_count',
      'mtk_last_paid_touch', 'mtk_time_since_last_paid_touch', 'mtk_time_to_conversion',
      'mtk_journey_string'
    ];

    // Every mtk_* value the event carries, minus the excluded and the retired.
    function keysFrom(data) {
      var out = [];
      for (var key in data) {
        if (!data.hasOwnProperty(key)) continue;
        if (key.indexOf('mtk_') !== 0) continue;
        if (isLegacy(key)) continue;
        if (EXCLUDE.indexOf(key) > -1) continue;
        out.push(key);
      }
      out.sort(function (a, b) {
        var ia = PRIORITY.indexOf(a), ib = PRIORITY.indexOf(b);
        if (ia === -1 && ib === -1) return a < b ? -1 : a > b ? 1 : 0;
        if (ia === -1) return 1;
        if (ib === -1) return -1;
        return ia - ib;
      });
      return out;
    }

    function attributionData() {
      var dl = window.dataLayer || [];
      for (var i = dl.length - 1; i >= 0; i--) {
        if (dl[i] && dl[i].event === 'mtk_attribution') return dl[i];
      }
      return null;
    }

    var tries = 0;
    function fill() {
      var data = attributionData();
      if (!data || !document.querySelector('form')) {
        if (tries++ < 1200) return window.requestAnimationFrame(fill);
        return;
      }
      var params = new URLSearchParams(window.location.search);
      var keys = keysFrom(data);
      var changed = false;
      for (var i = 0; i < keys.length; i++) {
        var key = keys[i];
        if (data[key] === undefined) continue;
        // Squarespace prefills a Hidden field from SQF_ + its Field Name,
        // uppercased with spaces as underscores.
        var sqf = 'SQF_' + (RENAME[key] || titleOf(key)).toUpperCase().replace(/ /g, '_');
        if (params.has(sqf)) continue;
        params.set(sqf, data[key] === null ? '' : String(data[key]));
        changed = true;
      }
      // Every value becomes a URL parameter and the page reloads with them, so
      // a long map is the thing that breaks this: browsers give up past a few
      // thousand characters. Trim with EXCLUDE if this ever gets close.
      if (changed && ('?' + params.toString()).length > 4000 && window.console && console.warn) {
        console.warn(
          '[MTK Squarespace] the prefill URL is ' + ('?' + params.toString()).length +
          ' characters; drop fields you do not need into EXCLUDE.'
        );
      }
      if (changed) window.location.search = '?' + params.toString();
    }

    if (document.readyState === 'loading') {
      document.addEventListener('DOMContentLoaded', fill);
    } else {
      fill();
    }
  })();
  </script>
<!-- End MTK Attribution Squarespace Companion Script -->