Cross-Domain Conversion Tracking For Landing Pages

<script>
(function() {
    // Step 1: Capture tracking IDs from the URL when visitors arrive
    var urlParams = new URLSearchParams(window.location.search);
    var clickIds = ['gclid', 'fbclid', 'msclkid', 'ttclid', 'li_fat_id'];
    
    clickIds.forEach(function(param) {
        var value = urlParams.get(param);
        if (value) {
            localStorage.setItem('_saved_' + param, value);
            console.log('Captured ' + param + ': ' + value);
        }
    });
    
    // Step 2: Add these tracking IDs to links going to your event landing pages
    var savedParams = {};
    clickIds.forEach(function(param) {
        var saved = localStorage.getItem('_saved_' + param);
        if (saved) {
            savedParams[param] = saved;
        }
    });
    
    // Only proceed if we have tracking parameters to add
    if (Object.keys(savedParams).length > 0) {
        // IMPORTANT: You may need to replace "eventrac.co.uk" if you use a custom domain for your eventrac landing page
            document.querySelectorAll('a[href*="eventrac.co.uk"]').forEach(function(link) {
            try {
                var url = new URL(link.href);
                
                // Add each tracking parameter to the link if not already present
                Object.keys(savedParams).forEach(function(param) {
                    if (!url.searchParams.has(param)) {
                        url.searchParams.set(param, savedParams[param]);
                    }
                });
                
                link.href = url.toString();
            } catch (e) {
                // Ignore any malformed URLs
            }
        });
        
        console.log('Landing page links decorated with tracking parameters');
    }
})();
</script>