You can do this:
<%= select(:preferences,
:job_history_filter_period,
ContactPreference::JOB_HISTORY_OPTIONS,
options = {},
html_options = {
:onChange => "new
Ajax.Request('/controller_name/modify_history_time_period/' +
this[this.selectedIndex].value, {asynchronous:true,
evalScripts:true});"
}
) %>
It's not as clean as the helper but gets the job done.
Cheers,
Atha