function DisplayAlert(id,left,top) {
document.getElementById(id).style.left=left+'px';
document.getElementById(id).style.top=top+'px';
document.getElementById(id).style.display='block';
}

function validate_mail(field)
{
with (field)
  {
  apos=value.indexOf("@");
  dotpos=value.lastIndexOf(".");
  if (apos<1||dotpos-apos<2)
    {DisplayAlert('AlertBox');return false;}
  else {return true;}
  }
}

function validate_form(thisform)
{
with (thisform)
  {
  if (validate_mail(mail)==false)
    {mail.focus();return false;}
  }
}