form 表单提交组数据

可以生成groups 这样的数据，有很多个name为groups的数据：

--省--
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="town"

--市--
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="country_level"

--县--
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="groups"

2
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="groups"

1
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="groups"

5
------WebKitFormBoundarygPDAAsQkGvfNokeb
Content-Disposition: form-data; name="groups"

3
------WebKitFormBoundarygPDAAsQkGvfNokeb--