$(document).ready(function() {

$(':submit', "#commentform").removeAttr('disabled');

$("#sub").click( function() {
 $.post( $("#commentform").attr("action"),
         $("#commentform :input").serializeArray(),
         function(info){ $("#result").html(info);
   });
clearInput();
});
 
$("#commentform").submit( function() {
  return false;
});
function clearInput() {
    $(':submit', "#commentform").val('Comment sent.')
                                .attr('disabled', 'disabled');
}
});