zend framework - populate a 2nd filtering select based on the first - ZF and dojo -

i have response json string returned first fs(filteringselect) contents of second , can't make load it. i've tried store.clearonclose , doesn't work , javascript valid. how do ? here code form 2 filteringselects:

$category=new zend_dojo_form_element_filteringselect("category");     $category->setlabel("category");     $category->setattrib("id","category")             ->setattrib("onchange","                                     var cat=dojo.query('#category ')[0].value;                                     dojo.xhrpost({                                             url: 'getsubcategories',                                            handleas: 'text',                                            content: { category:cat } ,                                             load: function(data, ioargs) {                                                       var store=subcatstore.store;                                                       store.data=data;                                                       store.close()                                             },                                            error: function(data,ioargs) {                                                    if(typeof data== 'error'){                                                         console.warn('error');                                                         console.log(ioargs);                                                      }                                                  }                                       });                                    "     );     $category->setoptions(array(         "autocomplete"=>false,         "storeid"=>"category",         "storetype"=>"dojo.data.itemfilereadstore",         "storeparams"=>array("url"=>"getcategories"),         "dijitparams"=>array("searchattr"=>"name")                           )                           )             ->setrequired(true);     $subcategory=new zend_dojo_form_element_filteringselect("subcategory");     $subcategory->setlabel("sub category")             ->setattrib("id","subcategory");     $subcategory->setoptions(array(         "autocomplete"=>false,         "storeid"=>"subcatstore",         "jsid"=>"subcatstore",         "storetype"=>"dojo.data.itemfilereadstore",         "storeparams"=>array("clearonclose"=>true,"url"=>"getsubcategories"),         "dijitparams"=>array("searchattr"=>"name")))             ->setrequired(true); 

i've red on net way , element of 2nd dropdown , passed values when 1st changes. wrong ? tnx attention.

i dont know zf, how in js :

new dijit.form.filteringselect({ id: "country", name: "country", store: countrystore, required: false, onchange: function(country) {     dijit.byid('state').query.countryid = country ; }, searchattr: "name" },"country");