Top.close not working in FF (logout button)

This works with Internet Explorer but not Firefox. It seems to set the cookie in FF but does not close window. Any other options besides top.close that would work with both FF and IE? We cannot use window.close because it doesn’t work with frames. Thanks team…

if (confirm(“Logout Confirmation?”))

{

document.cookie = “DomAuthSessId” + “=” + “” + “; expires=Friday, 01-Jan-1904 08:00:00 GMT ; path=/”;

top.close();

}