function checkRef() {
	var frm = window.document.ftfrm;
	var ref = new String(frm.trackref.value);
	var zpos = ref.indexOf("z");
    if(zpos==0) {
		alert("Please enter the full unique reference number");
		return false;
	} else {
		var mref=ref.substr(0,zpos);
		var jref=ref.substr(zpos+1);
		if(mref=="15920" || mref=="21950") {
			window.open("https://emea.netdespatch.com/mba/"+mref+"x0/track/index.php3?type=1&ref="+jref, target="_blank");
//			frm.action=;
			return false;
		} 
	}
	alert("Invalid unique reference number");
	return false;
}