Blank Application Close Button

I’m using a blank application to perform back-end processing. That application is linked to an upload form and is contained using a vertical menu. It is not obvious to users that they need to manually close a tab because all they see is a blank tab under the menu.

I inserted the following HTML in a stand-a-lone blank form with success when running outside the menu environment. It otherwise fails when run from the menu or the front-end form loaded from the menu. The question, how do I change the following to work within my project or is there a better solution?

?>
<html>
<head>
<h2>Results…</h2> <br />
<button type=“button” onclick=“window.open(’’, ‘_self’, ‘’); window.close();”>Close Window</button>
</head>
</html>
<?php