function popup(url, name, width, height) {
	var left =  (screen.width - width) / 2
	var top = (screen.height - height) / 2
	window.open( url, name,  "width="+width+", height="+height+", left="+left+", top="+top+"");
}

window.onload = function()
{
	if( (nl_form = document.forms['newsletter_form']) != null)
		nl_form.onsubmit= function(){
			if(document.getElementById("radio_subscribe").checked)
				popup('newsletter_form.php?email=' + nl_form.email.value, 'newsletter_form', 200, 150);
			else
				popup('newsletter_unsubscribe.php?email=' + nl_form.email.value, 'newsletter_form', 200, 150);
			return false;			
		};
}