jQuery Grid Plugin - jqGrid

Hi,

     I am performing number validaton on specific column. when i click on submit it validates the input and if it is true i return [true,""]. but at the top of the form dialog an empty message is displaying with red color background and not able to save the data.

Please check my code

function CheckForN(value, colname) {
    debugger;
    var a = Number(value);
    var msg ;
    if ( a.toString() == 'NaN' || typeof a == 'undefined' || typeof a == null || typeof a == 'null' || a == NaN) {
        msg = 'Enter Valid Number for ' + colname;
        $('#divModal').html(msg);
        $("#divModal").dialog("option", "buttons", { "Close": function () { $(this).dialog("close"); $("#divModal").html("");  } });
        //$('#' + id[0].trim()).focus();
        //$('#closedialog').click();
        //$('#info_dialog').hide()
        //$('#divModal').dialog({ open: function (event, ui) { $('#divModal').focus(); } });
        $('#divModal').dialog('open');
        //$('#Phone').keyup();              
        //$('#info_dialog').focus(function () { $('#info_dialog').hide(); });
        //$('#info_dialog').hide()     
        return [false, msg];
    }
    else {
       // $('#FormError').hide();
        return [true, ""];
        msg = "";
    }
    return [true,""]
}

i am calling above function for number column. for all other columns it is working fine. Please give your suggestions.