function validateContactForm(theForm) {
var reason = "";

  reason += validateEmpty(theForm.yourname,"Your name has");
  reason += validateEmpty(theForm.emailaddress,"Your email address has");
  reason += validateEmpty(theForm.phonenumber,"Your phone number has");
      
  if (reason != "") {
    alert("You left some required entries blank:\n\n" + reason);
    return false;
  }

  return true;
}

function validateEmpty(fld,fldname) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#ff6666'; 
        error = fldname + " not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}