js实现失去焦点验证

    <script>
        $(function () {

            var input_username = $('#input_username');
            var span_result = $('#span_result');

            input_username.blur(function () {
                var username = input_username.val();

                if(username == ""){
                    return;
                }

                $.ajax(
                    {
                        url:'/check',
                        data:{'username':username,'type':'hasuser'},
                        type:'post',
                        dataType:'json',
                        async:'true',
                        success:function (data,status,xhr) {
                            console.log('成功获取服务器响应');
                            console.log(data);
                            console.log(status)
                            var msg = data.msg;
                            if(msg=="ok"){
                                span_result.text("该用户名可以使用");
                                span_result.css("color","blue");
                            }else{
                                span_result.text("该用户名已被占用");
                                span_result.css("color","red");
                            }

                        },
                        error:function (xhr,status,error) {
                            console.log('获取服务器响应失败');
                            console.log(error);
                            console.log(status)
                        }
                    }
                );
            });



        });

    </script>

后台的获取是和平时获取方式一样，是post就用post方式获取，是get就用get方式获取。最后返回的时候以json格式返回。

class CheckHandler(MyRequestHandler):
    def get(self, *args, **kwargs):
        pass

    def post(self, *args, **kwargs):
        # hasuser findavatar
        type = self.get_body_argument('type')


        username = self.get_body_argument('username',None)
        print('获取到的username:----->',username)

        if type=='hasuser':
        #利用ｄｂｕｔｉｌ去根据ｕｓｅｒｎａｍｅ查询
        #tb_user表中是否已有该用户名
            if self.application.dbutil.hasUser(username):
                result = dict(msg='no_ok')
            else:
                result = dict(msg='ok')
            self.write(result)

        #查询头像
        if type=='findavatar':
           avatarname = self.application.dbutil.findAvatar(username)
           if avatarname:
               result = dict(msg=avatarname)
           else:
               result = dict(msg="default_avatar.png")

           self.write(result)