I want to sum Textbox value with gridview column credit value as in image,i highlighted Credit total 5000 with textbox(txtamount).

<script type="text/javascript">
    $(function () {
        $(".js-example-placeholder-single").select2({
            placeholder: "Select",
            allowClear: true
        });
    });
    //On UpdatePanel Refresh
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    if (prm != null) {
        prm.add_endRequest(function (sender, e) {
            if (sender._postBackSettings.panelsToUpdate != null) {
               $(".js-example-placeholder-single").select2({
                  placeholder: "Select",
                  allowClear: true
               });
                 $(function () {
        CalculateDebitCredittotal()
    });
            }
        });
    };
     $(function () {
        CalculateDebitCredittotal()
    });
 
    function CalculateDebitCredittotal() {
        var creditTotal = 0;
        var debitTotal = 0;
        $("[id*=gvtrans] tr:has(td)").each(function () {
        
            if ($(this).find($("[id*=txtCredit]")).val() != "" && $(this).find($("[id*=txtCredit]")).val() != undefined)
            {
                creditTotal += parseFloat($(this).find($("[id*=txtCredit]")).val());
            }
           
            if ($(this).find($("[id*=txtDebit]")).val() != "" && $(this).find($("[id*=txtDebit]")).val() != undefined)
            {
                debitTotal += parseFloat($(this).find($("[id*=txtDebit]")).val());
            }
            $(this).find($("[id*=lblTotaldr]")).html("Total:" + debitTotal.toString());
            $(this).find($("[id*=lblTotalcr]")).html("Total:" + creditTotal.toString() );
        });
        $("[id*=hfCredit]").val(creditTotal);
        $("[id*=hfDebit]").val(debitTotal);
    }
</script>