Cannot insert data by pressing Enter in Combogrid after selection

I am using a combogrid for load data to insert into datagrid. I call the insert data to datagrid in onSelect. Thats mean when i select any data or press down key to scroll all my data then those rows will be selected any inserted automatically . But i want to look through the rows but only when i press inter then the selected row will be inserted.

I am trying this by using KeyUp function. But this wont working.

This is my previous code:

Combogrid add to row

   function combogridData() {
        var g = $('#itemListGrid').combogrid('grid');   // get datagrid object
        var r = g.datagrid('getSelected');  // get the selected row
        $('#itemListGrid').keyup(function(e){
        if(e.keyCode == 13)
        {
            addrowtogrid(r);
        }
        });

        $('#itemListGrid').combogrid('clear');
    }

My Combogrid :

 <select id="itemListGrid" class="easyui-combogrid" style="width:100%"  data-options="

  panelWidth: 600,
  loader: myloader,
  mode: 'remote',
  idField: 'book_id',
  textField: 'name',
  method: 'get',
  value: '',
  columns: [[
      {field:'book_id',title:'Item ID',width:'7%'},
      {field:'name',title:'Book Name',width:'48%'},                                          
      {field:'retail',title:'retail',width:'5%',align:'right',hidden:true},
      {field:'local_sale',title:'local',width:'7%',align:'right'},
      {field:'whole_sale',title:'Whole',width:'8%',align:'right'},
      {field:'isbn',title:'ISBN',width:'15%'},
      {field:'authors',title:'Authors',width:'15%'},
       ]],
 fitColumns: true,
 labelPosition: 'top',
 onSelect:combogridData ">

I am trying by using this code :

        function combogridData() {
        var g = $('#itemListGrid').combogrid('grid');   // get datagrid object
        var r = g.datagrid('getSelected');  // get the selected row
        $('#itemListGrid').keyup(function(e){
        if(e.keyCode == 13)
        {
            addrowtogrid(r);
        }
        });

        $('#itemListGrid').combogrid('clear');
    }

I got My Own solution. don't need to add onSelect anymore. Just added

      $('#itemListGrid').combogrid('textbox').bind('keyup', function(e){
      if (e.keyCode == 13){   // when press ENTER key, accept the inputed value.
      var g = $('#itemListGrid').combogrid('grid'); //get the combogrid
      var r = g.datagrid('getSelected'); //get selected value
      addrowtogrid(r); //add to another datagrid
    }
    }); 

under JQuery document.ready(). It's working perfectly. Thanks.