app/views/recurring_todos/toggle_star.js.erb
<%- if @saved -%>
$('div#recurring_todo_<%= @recurring_todo.id %> a.star_item img').toggleClass('starred');
<%- else -%>
TracksPages.page_error('<%= t('todos.error_starring_recurring', :description => @recurring_todo.description) %>');
<%- end -%>