Adding blank option to rails select tag

Question

Im using jquery chained, and Im trying to get the second drop down list to gray out if the first has a blank option selected. Im assuming I need a blank option in the second list for it to lock out, but I'm not sure how to add a blank option. Here is the select option

<%= select_tag :equipment, options_for_select(Equipment.all.collect
                                            { |e| ["#{e.model} - #{e.serialNum}",e.id, 
                                            :class =>"#{e.handReceipt}"]},
                                            html_options = {:id=>'equipment'}) %>

The first drop down list lets you select the hand receipt type, and with jquery chained, the second list only shows records with the appropriate hand receipt attribute.

How would I add a blank option to the above select?

Edit- Here is what I've tried so far -

<%= select_tag :equipment, 
     options_for_select(  [["--",""],
                          Equipment.all.collect{ |e|
                          ["#{e.model} - #{e.serialNum}",
                          e.id, :class =>"#{e.handReceipt}"]}],
                          html_options = {:id=>'equipment'}) %>

This results in an improper display of the list-

<select id="equipment" name="equipment">
   <option value="">--</option>
   <option value="[&quot;M4 - W432156&quot;, 10, {:class=&gt;&quot;Arms Room&quot;}]">[&quot;PSN-13 - 176985&quot;, 1, {:class=&gt;&quot;Commo&quot;}]</option>
</select>

Instead of showing all the records in the table, it just shows a blank option and the second option.

<%= select_tag :equipment, 
     options_for_select(  :include_blank => true,
                          Equipment.all.collect{ |e|
                          ["#{e.model} - #{e.serialNum}",
                          e.id, :class =>"#{e.handReceipt}"]},
                          html_options = {:id=>'equipment'}) %>

Results in the following error -

C:/Users/Sam/Documents/ruby/btrp/app/views/vehicles/edit.html.erb:19: syntax error, unexpected ',', expecting tASSOC
                          e.id, :class =>"#{e.handReceipt}"]},

Answer 1

Your parameters at options_for_select is wrong, I think that's the right way:

<%= select_tag :equipment,
      options_for_select(Equipment.all.collect { |e|
                           ["#{e.model} - #{e.serialNum}", e.id,
                            { :class =>"#{e.handReceipt}" }]}), 
      :include_blank => true,
      :id => 'equipment' %>

Read more at:

http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-options_for_select

http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html