One question about Dynamic Select Menus

rubyonrails-talk
1

Hi all, Merry X'mas first :slight_smile:

I have "Product","Category","Subcategory" 3 Model, and when new "Product", I want to use "Dynamic Select Menus" just like Ryan mentioned in #88 Dynamic Select Menus - RailsCasts

I have everything down. But when I visit the js file, I got following error

Showing app/views/javascripts/dymanic_categories.js.erb where line #3 raised:

You have a nil object when you didn't expect it! You might have expected an instance of Array. The error occurred while evaluating nil.each

Extracted source (around line #3):

1: // javascripts/dynamic_categories.js.erb 2: var subcategories = new Array(); 3: <% for subcategory in @subcategories -%> 4: categories.push(new Array(<%= category.id %>, '<%=h subcategory.subcategory_name %>', <%= subcategory.id %>)); 5: <% end -%>

Anyone got an idea, how does it happen?

2

What does the controller set @subcategories to before rendering the javascript?

–wpd

3

Hi Partrick, Before the controller rendering the Javascript, @subcategories = Subcategory.find(:all)

4

Showing app/views/javascripts/dymanic_categories.js.erb where line #3 raised:

"dymanic"?

5

Hey, Eric Thank you very much for help. I checked my codes again, yes I made a typo here, it should be "dynamic_categories" here And now when I visit app/views/javascripts/dynamic_categories.js.erb I can get the array

But, question comes again :frowning:

I can get category and subcategory list in my item/new view But, when I change the value of category the value of subcategory doesn't change!

I checked with web inspector, I got this error message"TypeError: Value undefined (result of expression document.observe) is not object." It seems my result of document.observe is not correct?

How can I fix it?

6

OK, guys Finally I figured it out. I missed the <%= javascript_include_tag :defaults %> in my layout. Now everything goes fine. Thank you very much for your help.