testing page

<script>
(function() {
const stag = new URLSearchParams(window.location.search).get('stag');
if (!stag) return;

const observer = new MutationObserver(() => {
const input = document.querySelector('input[name="stag"]');
if (input) {
input.value = stag;
observer.disconnect(); // stop once found
}
});

observer.observe(document.body, {
childList: true,
subtree: true
});
})();
</script>