function MessageFocus() {
  if (document.stf.message.value == "Message") {
    document.stf.message.value = "";
  }
}

function Validate() {
  if (document.stf.yName.value == "") {
    alert("Please enter your name");
    document.stf.yName.focus();
    return false;
  } else if (document.stf.yEmail.value == "") {
    alert("Please enter your e-mail address");
    document.stf.yEmail.focus();
    return false;
  } else if (!filter.test(document.stf.yEmail.value)) {
    alert("Please enter one valid e-mail address");
    document.stf.yEmail.focus();
    return false;
  } else if (document.stf.fName.value == "") {
    alert("Please enter your friend's name");
    document.stf.fName.focus();
    return false;
  } else if (document.stf.fEmail.value == "") {
    alert("Please enter your friend's e-mail address");
    document.stf.fEmail.focus();
    return false;
  } else if (!filter.test(document.stf.fEmail.value)) {
    alert("Please enter one valid e-mail address");
    document.stf.fEmail.focus();
    return false;
  }
  return true;
}