Open php script in same tab

I have the following code

                    $upc = $_POST['UPC'];
                    $_SESSION['UPC'] = $_POST['UPC'];
                    if(strlen($upc)< 5)
                    {
?>
                        <script type="text/javascript">
                        <!--
                        open('TestScale2.php');history.back();
                        //-->\
                        </script>

<?php

This will open TestScale2 in a new tab. How can I open it in the same tab?

Try

open('TestScale2.php','_self');history.back();

junior-helper -

Thanks.

Regratably, it does not work.

try

window.open("whatever.php","_self")

"open" opens a new window, to change the current one, window.location.assign("url")