var submitcount=0;

function reset() {
document.emailform.name.value="";
document.emailform.email.value="";
document.emailform.comments.value="";
}

function checkFields() {
  if (document.emailform.name.value == "") {
    alert("Please enter your name.");
    return false;
  }
  if (document.emailform.email.value == "") {
    alert("Please enter your email.");
    return false;
  }
  if (document.emailform.comments.value == "") {
    alert("Please enter your comments.");
    return false;
  }
  if (submitcount == 0) {
    submitcount++;
    return true;
  } else {
    alert("This form has already been submitted.  Thanks!");
    return false;
  }
}