function CheckEmail() {
	var badAddress = "That does not appear to be a valid email address?\nPlease try again ...";
	var emptyField = "Please complete all the fields before submitting the form! Please try again...";
	var firstname = document.forms[0].firstname.value
	var lastname = document.forms[0].lastname.value
	var email = document.forms[0].email.value
	var AtPos = email.indexOf("@")
	var StopPos = email.lastIndexOf(".")
	var Message = ""
	
	if (firstname == "" || lastname == "") { Message = emptyField }
	if (email == "") { Message = badAddress }
	if (AtPos == -1 || StopPos == -1)  { Message = badAddress }
	if (StopPos < AtPos) { Message = badAddress }
	if (StopPos - AtPos == 1) { Message = badAddress }
	
	if (Message != "") {
		alert(Message);
	} else {
		alert("Thank you " + firstname + ". Your email address:\n" + email +"\nhas been added to the mailing list.");
		document.forms[0].submit();
	}
}