Question

I was just going through this

old rails cast episode, and one thing it mentions is the (now obsolete, apparently) link_to_function code. One interesting snippet it mentions is

 link_to_function "Add a Task" do |page|
    page.insert_html :bottom, :tasks, :partial => 'task', :object => Task.new
  end

In short, clicking the “Add a Task” link appends the “task” partial to the page without ajax.

I’m familiar with how to do this in Rails 3/3.1 via AJAX and/or manual javascript, but how do you pull in a template partial on the fly without touching ajax?

Answer 1

It just simply stores the html content within the javascript code, which it’s rendered while the page is rendered. So when you click “Add a task” the partial is already there escaped in the javascript code of the add task action. Just take a look to the content of the page with firebug.

Also the docs shows that the instert_html looks like this for prototype:

def insert_html(position, id, *options_for_render)
  content = javascript_object_for(render(*options_for_render))
  record "Element.insert(\"#{id}\", { #{position.to_s.downcase}: #{content} });"
end

So you can see that the content is actually the task partial, and it’s inserted into javascript code.
Also i have to mention that this is an obtrusive way to use javascript.

Take a look at the docs.