function validEmail(email) { 
	var invalidChars = " /:,;"
	if (email == "") return false
	atPos = email.indexOf("@",1) 
	if (atPos == -1) return false 
   if (email.indexOf("@",atPos+1) > -1) return false 
	periodPos = email.indexOf(".",atPos) 
   if (periodPos == -1) return false
   if (periodPos+3 > email.length) return false 
	for (i=0; i<invalidChars.length; i++) {
		badChar = invalidChars.charAt(i);
		if (email.indexOf(badChar,0) > -1) return false
		} 
	return true 
} 

function Pup() {
	if (validEmail(document.formpie.email.value)) {
		var co=document.formpie.subscribe.length;
		for (ii=0;ii<co;ii++) if (document.formpie.subscribe[ii].checked==true) var sub=document.formpie.subscribe[ii].value;
		url='http://www.sp.nl/include/poster_pop.php?sub='+sub+'&email='+document.formpie.email.value;
		winStats='toolbar=no,menubar=no,status=no,scrollbars=yes,resizable=yes,width=280,height=250'
		if (screen.width == 1024) {L='220';H='112';}
		else {L='115';H='0';}
		if (navigator.appName.indexOf('Microsoft')>=0) winStats+=',left='+L+',top='+H
		else winStats+=',screenX='+L+',screenY='+H
		hup=window.open(url,'a1',winStats)
		}
	else {
		alert("Sorry, onverwerkbaar e-mailadres!");
		return false;
		}
}