Button click event only.
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js" type="text/javascript"></script>
<script language="javascript" type="text/javascript">
$(document).ready(function () {
$("#btnext").click(function () {
window.open("HTMLPage.htm", "PopupWindow", "width=600,height=600,scrollbars=yes,resizable=no");
});
});
</script>