document.observe('dom:loaded', function() {

    FC.DependentFields.addRule(
        'from_courier',                     // unique rule identifier
        {
            field: 's_method_freeshipping_freeshipping',        // field to watch
            value: true,                        // value to compare with field value, can be an array
            dependentField: ['billing:city'],// dependent field, can be an array
            match: 'hidden',
            unmatch: 'optional' // field status, when field.value equals value
        }
    );
    FC.DependentFields.addRule(
        'from_store',                     // unique rule identifier
        {
            field: 's_method_freeshipping_freeshipping',        // field to watch
            value: true,                        // value to compare with field value, can be an array
            dependentField: ['billing:city','billing:street1'],// dependent field, can be an array
            match: 'hidden',
            unmatch: 'optional' // field status, when field.value equals value
        }
    );

});