function isValid(emailexp, f) {
        return emailexp.test(f);
     }
 
function validate() {
 if (document.forms[0].fName){
  var f = document.forms[0].fName;
  if (f.value == ""){
   alert("Please enter your first name.");
   f.focus();
   return false;
  } 
 }
 if (document.forms[0].lName){
  var f = document.forms[0].lName;
  if (f.value == ""){
   alert("Please enter your last name.");
   f.focus();
   return false;
  } 
 }
  if (document.forms[0].email){
  var f = document.forms[0].email;
  var emailexp = /^[^@\s]+@([-a-z0-9]+\.)+[a-z]{2,}$/i;
  if (f.value == ""){
   alert("Please enter your email address.");
   f.focus();
   return false;
  } else if (!isValid(emailexp,document.forms[0].email.value)) {
   alert("Your email address is not in the correct format.");
   f.focus();
   return false;
  } 
 }
  if (document.forms[0].subject){
  var f = document.forms[0].subject;
  if (f.value == ""){
   alert("Please enter a subject.");
   f.focus();
   return false;
  } 
 }
 
}