var formWindow;

function OpenFormWindow(url) {
    var pu_win_settings = "resizable=1,location=0,directories=0,status=0,menubar=0,scrollbars=1,toolbar=0,width=350,height=480";
	if (formWindow && !formWindow.closed) {
		formWindow.location = url;
		formWindow.focus();
	} else { 
		formWindow=window.open(url, "newsletter_form", pu_win_settings);	
	}
}