layui sleect获取value值

<div class="layui-form-item">
              <label for="username" class="layui-form-label">
                  <span class="x-red">*</span>父级分类
              </label>
              <div class="layui-input-inline">
                <select name="modules" name="category" lay-filter="parent">
                   {volist name="$class_info" id="vo"}
                      <option value="{$vo.id}">{$vo.class_name}</option>
                    {/volist}
                </select>

              </div>
          </div>

layui.use(['layer', 'form'], function(){
            var layer = layui.layer,form = layui.form;
             var category = 0;
              var categoryName = '';
              form.on('select(parent)', function (data) {
                  category = data.value;
                  categoryName = data.elem[data.elem.selectedIndex].text;
                  form.render('select');
                  console.log(category)
              })

          });