js跳转新地址

<select name="select" class="serchtwo" onchange="window.open(this.options[this.selectedIndex].value,'_Blank')" id="loginSelect"   onkeydown="enterSubmit(event)">
          <option selected>集团相关产业网站链接</option>
          <option value="http://www.dbn.com.cn">大北农</option>
          <option value="http://www.aweb.com.cn">农博网</option>
          <option value="http://www.agrosino.com/">绿色农华</option>
          <option value="http://www.zgnmdx.com">农民大学</option>
          <option>猪育种公司</option>
        </select>