<select size="1" class="easyui-combobox" > <option value="1">1</option> <option value="2" disabled>2</option></select>
<style>.combobox-item-disabled{ opacity: 0.5; filter: alpha(opacity=50);}</style>
var cc = $('#cc');var data = cc.combobox('getData');data[1].disabled = true;cc.combobox('loadData', data);