$('#reg_btn1').on('click', function(e) {

    var objectArray = $("#register-form :input").serializeArray();
    var data = {};
    var data = JSON.stringify(objectArray);

    data = "reg=" + data;
    alert(data);

     $.ajax({
         type: "POST",
         url: "RegisterServlet",
         data: data,
         dataType: "json",
         success: alert("is k")
     });

});