Insta OAuth Callback

<!doctype html><meta charset="utf-8">
<title>Meta OAuth Callback</title>
<meta name="robots" content="noindex">
<style>body{font-family:system-ui,sans-serif;margin:2rem}code{background:#f2f2f2;padding:.2rem .4rem;border-radius:6px}</style>
<h1>Meta OAuth Callback</h1>
<div id="out">Reading code…</div>
<script>
const p = new URLSearchParams(location.search);
const code = p.get('code'), err = p.get('error'), state = p.get('state');
document.getElementById('out').innerHTML = err
? `<p><b>OAuth error:</b> <code>${err}</code></p><p>Details: <code>${p.get('error_description')||''}</code></p>`
: code
? `<p><b>Copy this code:</b></p><p><code>${code}</code></p><p>State: <code>${state||'none'}</code></p>`
: `<p><b>No code found.</b></p>`;
</script>