function check() {
   var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
   var address = document.getElementById('email').value;
   if(reg.test(address) == false) {
      alert('The email address seems to be invalid.');
      document.getElementById('email').focus();
      return false;
   }
   else
   alert("You are now subscribed to Inger Forbes' newsletter on this address: "+address+".");
   return true;
   
}