Try opening a temp page instead, like this:
window.open('temp.php?cCodalu='+row.codalub);
Add a form to the page temp.php, and write some code like this:
<script type="text/javascript">
window.onload = function () {
document.forms[0].submit();
}
</script>
<form action="impress.php" method="post">
<input type="hidden" value="<?php echo $_REQUEST['cCodalu']?>">
</form>