// JavaScript Document
function validateOptin(formField) {
   var e = document.getElementById('optin-error').style;
   if(formField.value.match(/^[a-z_0-9\.\-]+@[a-z_0-9\.\-]+\.[a-z]/i)) {
     e.display = 'none';
     return true;
   } else {
   document.getElementById('optin-error').style.visibility="visible";
     e.display = 'block';
     return false;
   }
}