/////////////////////////////////////////////////
/////////////////////////////////////////////////
function check_form(form) {
   // error message string
   var str = '';
   var email = form.email.value;
   var reg = /^(\w+(?:\.\w+)*)@((?:\w+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i;

   if(!email)
      { str += "You must enter an email address.\n"; }

   if(email && !reg.test(email)) {
      flag = 1;
      str += '"' + email + '"' + " is not a valid email address.\n";
   }

   if(str != '') { alert(str); return false; }

   return true;
}