After DOM Load in body

$.validator.addMethod("bd_phone",function(phone){

  var reg = /(^(\+88|0088)?(01){1}[56789]{1}(\d){8})$/;

    if(reg.test(phone)){

        return true;

    }

    return false;

},"");

if($(document.body).find('.minor').length){

    $("#publicReg").validate({

        rules: {

            birth_date: "required",

            district: "required",

            gender: "required",

            police_station: "required",

            full_name_bangla: "required",

            village_ward: "required",

            full_name_english: "required",

            post_code: "required",

            father_name: "required",

            mother_name: "required",

            occupation: "required",

            per_district: "required",

            mobile: {

              required:true,

              bd_phone:true

            },

            per_police_station: "required",

            per_village_ward: "required",

            per_post_code: "required"

        }

    });

}