[Ruby] JavaScript in FormHelpers

[Neil Moomey]

How do I add JavaScript to FormHelper tags?  For example in a radio button I
want to display something like :

<input value="Address" name="searchby" type="radio" id="Address"
onClick="javascript:redirect('QueryA1R1.rhtml')" />

but I want to use a FormHelper like:
<%= radio_button "post", "category", "rails" %>

Also, why do Form helpers always output arrays for the name attribute?
name=post[category]

Thanks

Neil