function isReady(form) {
  if (isFilled(form.username) == false) {
    alert("Please enter your name.");
    form.username.focus();
    return false;
  }
  if (isEmail(form.email) == false) {
    alert("Please enter valid email address.");
    form.email.focus();
    return false;
  }
  if (isFilled(form.message) == false) {
    alert("Please include a message.");
    form.message.focus();
    return false;
  }
}
function isEmail(elm) {
  if (elm.value.indexOf("@") != "-1" && elm.value.indexOf(".") != "-1" && elm.value != "")
    return true;
  else return false;
}
function isFilled(elm) {
  if (elm.value == "" || elm.value == null)
    return false;
  else return true;
}