PM popup

How do i change this code so that it ownt open the message in a new window but instead in the window that the surfer is using?

<script language="JavaScript">
<!--
function confirm_newpm()
{
input_box=confirm("Du har ett nytt meddelande, klicka p? ok f?r att titta p? den.");
if (input_box==true)

{
// Output when OK is clicked
window.open('private.php?s=$session[sessionhash]','pmnew','width=600,height=500,menubar=yes,scroll bars=yes,toolbar=yes,location=yes,directories=yes, resizable=yes,top=50,left=50');
}

else
{
// Output when Cancel is clicked
}

}
-->
</script>

Replace

window.open('private.php?s=$session[sessionhash]','pmnew','width=600,height=500,menubar=yes,scrollbars=yes,toolbar=yes,location=yes,directories=yes,resizable=yes,top=50,left=50');

with

window.location="private.php?s=$session[sessionhash]";

Thanx it worked.