Loading up a dropdown when the parent drop down is selected

[Vibindas]

Hi all,

I'm new to ruby on rails and currently working on a project.I need a small help from you guys out der. I have a parent drop down which has some categories , on selecting this drop down i need to load up the child dropdown with the courses corresponding to the category selected in the parent dropdown. I tried using the ajaxupdater but it was not working.Can any one please help me to get a solution for this.(If some code samples are der it would be really helpful)......

Thanks

Vibin