Rails onblur事件 Ajax验证表单

            <tr>
                <td>
                    用户名：
                </td>
                <td>
                    <%= text_field("user","name", :size=>"20" , :onblur =>remote_function(
                                :update => :result,
                                :url => {:controller=>:users,:action => :check_name},
                                :with => "'user_name=' + value ")) %>
                    <span id="result"></span>
                </td>
            </tr>