use BitrixMainPageAsset;
use BitrixMainPageAssetLocation;
Asset::getInstance()->addString("<script>***</script>", true, AssetLocation::AFTER_JS);
// AssetLocation::BEFORE_CSS;
// AssetLocation::AFTER_CSS;
// AssetLocation::AFTER_JS_KERNEL
// AssetLocation::AFTER_JS

$connection = BitrixMainApplication::getConnection();
$sqlHelper = $connection->getSqlHelper();
$recordset = $connection->query("SELECT * FROM dbname");
while ($record = $recordset->fetch()){ ...  }