jQuery Validation plugin: submitHandler not preventing default on submit when making ajax call to servlet - return false not working

Question

I have a simple form that uses jquery and a servlet. The jquery makes an ajax call to the servlet, the servlet makes some server side calculations, then displays the result

Answer 1

I know many people have answered but i'll show my entire code in 2020

$(document).ready(function () {
    $("#PaymentModeForm").validate({
        rules: {
            "f_cheque_mode_display": {
                required: true,
            },
            "f_cheque_infavour": {
                required: true,
            },
            "f_cheque_payablein": {
                required: true,
            },
            "f_cheque_address": {
                required: true,
            },
            "f_cheque_mobileno": {
                required: true,
            },
            "f_bank_mode_display": {
                required: true,
            },
            "f_bank_beneficiary": {
                required: true,
            },
            "f_bank_acc": {
                required: true,
            },
            "f_bank_bankname": {
                required: true,
            },
            "f_bank_branchname": {
                required: true,
            },
            "f_bank_ifsc": {
                required: true,
            },
            "f_cod_mode_display": {
                required: true,
            },
            "f_cod_mode_charges": {
                required: true,
            },
            "f_razorpay_mode_display": {
                required: true,
            },
            "f_razorpay_key": {
                required: true,
            },
            "f_razorpay_secret": {
                required: true,
            }
        },
        messages: {
            "f_cheque_mode_display": {
                required: "Enter Payment mode display on website"
            },
            "f_cheque_infavour": {
                required: "Enter Infavour Of",
            },
            "f_cheque_payablein": {
                required: "Enter Payble In",
            },
            "f_cheque_address": {
                required: "Enter Courier Address",
            },
            "f_cheque_mobileno": {
                required: "Enter Mobile No",
            },
            "f_bank_mode_display": {
                required: "Enter Payment mode display on website"
            },
            "f_bank_beneficiary": {
                required: "Enter Beneficiary Name",
            },
            "f_bank_acc": {
                required: "Enter A/C No",
            },
            "f_bank_bankname": {
                required: "Enter Bank Name",
            },
            "f_bank_branchname": {
                required: "Enter Branch Name",
            },
            "f_bank_ifsc": {
                required: "Enter IFSC Code",
            },
            "f_cod_mode_display": {
                required: "Enter Payment mode display on website",
            },
            "f_cod_mode_charges": {
                required: "Enter COD Charges",
            },
            "f_razorpay_mode_display": {
                required: "Enter Payment mode display on website",
            },
            "f_razorpay_key": {
                required: "Enter Key Id",
            },
            "f_razorpay_secret": {
                required: "Enter Secret Key",
            }
        },
        submitHandler: function (form, e) { 
            e.preventDefault();
            var form = $(this);
            var url = "/PaymentModeSubmit";
            $.ajax({
            type: "POST",
            url: url,
            data: $("#PaymentModeForm").serialize(),
            success: function(data)
            {
                alert(data);
            }
            });      
        return false;
        }
    });
    return
});