Question

I am learning ruby on rails. In my project
I use collection_select. My code is

<%= collection_select(:sport_name,count,Sport.find( :all, :order => 'id' ), :id, :sport_name, {} ,
    {:selected      => ps.sport.id,
     :include_blank => "Select Sport",
     :onchange      => "hidvalue("+ps.sport.id.to_s+","+count.to_s+")",
     :style         => "margin:1px 0 0;width:210px;" }) %>

onchange works – selected doesn’t work

If I instead do

<%= collection_select(:sport_name,count,Sport.find( :all, :order => 'id' ),:id, :sport_name,
    {:selected      => ps.sport.id,
     :include_blank => "Select Sport",
     :onchange      => "hidvalue("+ps.sport.id.to_s+","+count.to_s+")" },
    {:style         => "margin:1px 0 0;width:210px;" }) %>  

onchange doesn’t work, but selected works. I want to use onchange and selected together. What is wrong with this code?

Answer 1

Well, “selected” is an option, but “onchange” is an HTML attribute that you want to assign to the generated HTML. Those two different types of things are supposed to be passed in to collection_select inside different arguments.

In particular, “selected” should be passed in as key/value pair in the fifth (“options”) hash, while “onchange” should be passed in as part of the sixth (“html_options”) hash.

See http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-collection_select for more information