# Reg date format **URL:** \ **Category:** Rails\ **Created:** [May 25, 2007, 10:47am UTC](https://www.ruby-forum.com/t/reg-date-format/105055 "2007-05-25T10:47:03Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![shiva](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/85e7bf/32.png) [@shiva](https://www.ruby-forum.com/u/shiva)\ **Post date:** [May 25, 2007, 10:47am UTC](https://www.ruby-forum.com/t/reg-date-format/105055/1 "2007-05-25T10:47:03Z")
in my page there is two drop down in which one should be year and month and another should be corresponding year and month date should be shown…for eg if i clicked may2007 ,in the next drop down it should list 31 days if i select feb 2007 it should show list of 28 days.is any one knows solution for this?please reply… ---
**Author:** ![shiva](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/85e7bf/32.png) [@shiva](https://www.ruby-forum.com/u/shiva)\ **Post date:** [May 25, 2007, 1:51pm UTC](https://www.ruby-forum.com/t/reg-date-format/105055/2 "2007-05-25T13:51:32Z")
try to use an onClick event with JS and render what you need through rjs to the second element. On 25 Mai, 10:47, Shiva K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![shiva](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/85e7bf/32.png) [@shiva](https://www.ruby-forum.com/u/shiva)\ **Post date:** [May 25, 2007, 4:39pm UTC](https://www.ruby-forum.com/t/reg-date-format/105055/3 "2007-05-25T16:39:06Z")
You can use observe\_field helper: [http://railsmanual.com/module/ActionView%3A%3AHelpers%3A%3APrototypeHelper/observe\_field](http://railsmanual.com/module/ActionView%3A%3AHelpers%3A%3APrototypeHelper/observe_field)