$('#btnsubmit').click(function(){
    var author = $('#author').val();
    var email = $('#email').val();
    var comment = $('#comment').val();
    var postData = {
        author: author,
        email: email,
        comment: comment
    };
    $.post('mailcode.php', postData,function(data,status){
         $('#emailresponse').html("Thank you!");
    });
});