javascript - Polymer 1.0 reading select value when there is an inside template(dom-repeat) in select tag -

i'm having trouble polymer 1.0 element. have print inside select every option of book size (a5, a4) , prices every selection(this information js array returned _returnselitemdataarr).
array data looks this:

_returnselitemdataarr: [array[id, name, extra], array[id, name, extra]]. 

here bit of source code :

    <select id="sizeselect" value="{{itm.id::change}}" aria-labelledby="sizelabel">                                             <template is="dom-repeat" items="{{_returnselitemdataarr(item, 'sizes')}}" as="itm">                                                 <option value="{{index}}" selected$="[[_computeselected(index, itm)]]">{{itm.name}} (+{{itm.extra}} lei)</option>                                             </template>         </select>   select compute function:       _computeselected: function(index, itm) {              return index+1===parseint(itm.id, 10);           }, 

problem when try selection value "#sizeselect" code : this.$.sizeselect.value console output of select value undefined . accesing select value seems problem when using polymer dom-repeat options. happens know how access select value ? note: have mention 'item' product, it's object contains information product

answer:
select element id under shadow-dom have use operator $$ . me this: this.$$('#sizeselect').value.

answer: select element id under shadow-dom have use operator $$ . me this: this.$$('#sizeselect').value.