function checkform()
{  
   var message = document.getElementById("message");
   var firstname = document.getElementById("firstname");
   var lastname = document.getElementById("lastname");
   var email = document.getElementById("email"); 
   var emailfilter = /^.+@.+\..{2,3}$/;

   // check for empty message box

   if (message.value == "")
   {  

      hideAllCFErrors();
      document.getElementById("messageError").style.display = "inline";
      document.getElementById("message").select();
      document.getElementById("message").focus();
      return false;
   }
   // check for empty first name input box
   else if (firstname.value == "")
   { 
      hideAllCFErrors();
      document.getElementById("firstnameError").style.display = "inline";
      document.getElementById("firstname").select();
      document.getElementById("firstname").focus();
      return false;
   }
   // check for empty last name input box
   else if (lastname.value == "")
   {   
      hideAllCFErrors();
      document.getElementById("lastnameError").style.display = "inline";
      document.getElementById("lastname").select();
      document.getElementById("lastname").focus();
      return false;
   }

   // check for empty email input box and test the filter
   else if ((email.value == "") || (!(emailfilter.test(email.value)))) 
   {
      hideAllCFErrors();
      document.getElementById("emailError").style.display = "inline";
      document.getElementById("email").select();
      document.getElementById("email").focus();
      return false;
   }
      return true;
}

function hideAllCFErrors()
{
   document.getElementById("messageError").style.display = "none";
   document.getElementById("firstnameError").style.display = "none";
   document.getElementById("lastnameError").style.display = "none";
   document.getElementById("emailError").style.display = "none";
}