function checkform ( form )
{
  if (form.realname.value == "") {
    alert( "Please enter your name." );
    form.realname.focus();
    return false ;
 } else if (form.email.value == "") {
    alert( "Please enter your email address." );
    form.email.focus();
    return false ;
 } else if (form.subject.value == "") {
    alert( "Please enter a subject." );
    form.subject.focus();
    return false ;
 } else if (form.message.value == "") {
    alert( "Please enter a message." );
    form.message.focus();
    return false ;
 }
 return true ;
}