function BATSubmit()
{
   if (checkfields()==false)
      return false;
    handle=EventHandlingNum(document.getElementById('c').value,document.getElementById('d').value,document.getElementById('e').value,1);
    document.batForm.a=handle;
}

<form name="batForm" ACTION="/bat.html" METHOD="POST" onSubmit="return BATSubmit()">