function endsWith(s, domain)
{
  var dl = domain.length;
  var sl = s.length;
  if (dl>sl) return false;

  if (s.substring(sl-dl)==domain) return true;
  
  return false;
}

function validEmail(s)
{
  var i,j;

	// trim
	s = s.replace(/^\s+|\s+$/g,"");
	
  if ((i=s.indexOf('@'))<0) return false;
  if ((s.indexOf('@',i+1))>=0) return false;
  if ((j=s.lastIndexOf('.'))<0) return false;
  if (i==0) return false;
  if ((j-i)<2) return false;

  s=s.substring(j+1).toLowerCase();

  switch (s.length)
  {
    case 2:
        break;
    case 3:
    case 4:
        if ((s!='com')&&
          (s!='edu')&&
          (s!='biz')&&
          (s!='mil')&&
          (s!='org')&&
          (s!='net')&&
          (s!='gov')&&
          (s!='arpa')&&
          (s!='int')&&
          (s!='firm')&&
          (s!='shop')&&
          (s!='web')&&
          (s!='arts')&&
          (s!='rec')&&
          (s!='info')&&
          (s!='name')&&
          (s!='nom'))
            return false;
      break;
    default:
      return false;
  }

  return true;
}

function checkData()
{
  var s =myform.email.value;
  
  if (!validEmail(s))
  {
    alert("Please enter a correct email address\nof the form someone@somedomain.com");
    myform.email.focus();
    myform.email.select();
    return false;
  }
  return true;
}