function checkForm() {
 var OK=false;
 if (OK=checkName()) {
 var address=document.contactForm.email.value;
 if (OK=checkMail()) {
	 if ((document.contactForm.Subscribe.checked) && (document.contactForm.Unsubscribe.checked)) {
 	 alert("Can't subscribe AND unsubscribe!\nPlease select only one box,\nor leave both blank.");
		OK=false;
	 }
	}
 }
 if (OK) document.contactForm.submit();
}

function checkMail(){
 var emailOK=false;
 if (document.contactForm.email.value.indexOf("@")==-1) alert("No '@' in address.");
 else {
	var adr=document.contactForm.email.value.split("@");
	if (adr[0].length<1) alert("Username absent.");
 	else if (adr[1].indexOf(".")==-1) alert("No dot in domain name.");
 	else {
	 var dmn=adr[1].split(".");
  if (dmn[0].length<3) alert("Domain name too short.");
	 else if (dmn[1].length<2) alert("Domain extension too short.");
  else emailOK=true;
	}
 }
 return emailOK;
}

function checkName() {
 var nameOK=false;
 var name=document.contactForm.realname.value;
 if (name.length<1) alert("Please enter your Name.");
 else nameOK=true;
 return nameOK;
}