var subwindow;
function popupwin(aDocument)
{
	if (!subwindow || subwindow.closed)
	{ 
		subwindow = window.open(aDocument,"subwindow","width=660,height=495,resizable,scrollbars=yes");
	} else {
		subwindow.document.location.href = aDocument;
		subwindow.focus();
	}
}