//billing address change complete
            $(document).on('change', '#' + that.getOptions().billingAddressContainer + ' input, #' + that.getOptions().billingAddressContainer + ' select', function(event){
                if(that.billingAddressNeedUpdate){
                    var varienForm = new VarienForm(that.getOptions().billingAddressContainer, true);
                    if( varienForm.validator.validate() ){
                        if(that.billingAddressTimeout){
                            clearTimeout(that.billingAddressTimeout);
                        }
                        that.billingAddressTimeout = setTimeout(function(){that.updateBillingAddress();}, 1000);
                    }
                }
            });