function isValidEmail(str) {
   return (str.indexOf(".") > 2) && (str.indexOf("@") > 0);
 
}

function checkInform(formname) {

	var Error="";
	if (formname.email.value=="") {
		Error="Missing email address\n";
	}
	
	if (! isValidEmail(formname.email.value)) {
		Error="Email format not allowed\n";
	}

	if (Error) {
		alert(Error);
		return false;
	} else {
		return true;
	}
}