Checkbox help ;)

A quick question I have working with a object in a rails 3 app and I
would like to retain the checkboxes ticked (for example there are 3
options if someone chooses option 1 and 2 and refreshes the page the
checkboxes 1 and 2 will remain ticked), this is very easy with radio
buttons but I am still trying to get my head around it with checkboxes.

here is some code:

<%= form_for(@user, :remote => true) do |f| %>

<%= f.check_box :a1, {:multiple => true}, "1", "" %>
<%= f.check_box :a1, {:multiple => true}, "2", "" %>
<%= f.check_box :a1, {:multiple => true}, "3", "" %>
<%= f.submit %>

<% end %>
<%= @user.a1.inspect %>
output from the inspect element:

“—\n- ‘’\n- ‘1’\n- ‘’\n- ‘2’\n- ‘’\n”
the user model has the a1 as a string in the db.

thanks in advance if anyone can help ,e

Regards Jon

Have a look at this page, at the “gotcha” around multiple => true.