var submitcount=0;

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

function checkFields() {                       // field validation -
if ( (document.emailform.name.value=="")  ||   // checks if fields are blank.
     (document.emailform.email.value=="") ||   // More validation scripts at
     (document.emailform.comments.value=="") ) // forms.javascriptsource.com
   {
   alert("Please enter your name, email, and comments, then re-submit this form.");
   return false;
   }

else 
   {
   if (submitcount == 0)
      {
      submitcount++;
      return true;
      }
   else 
      {
      alert("This form has already been submitted.  Thanks!");
      return false;
      }
   }
}