How to troubleshoot silently failing js in Rails?
firebug, infinite-scroll, jquery, ruby-on-rails-3.1, unobtrusive-javascript
Solution
As it turns out, Rails is not processing my second request as JS. More importantly, if the JS raises an exception, it will be converted to plain-text as explained here. Steve also shows how to debug ajax code, effectively answering both of my questions.
Problem
It should be noted that I am not very proficient at using Firebug, but I haven't found any errors that explain the following issue. I have a `feed.js.erb` file containing the following code: ``` var $foos = $('<%= escape_javascript(render(@foos)) %>'); $('#container').append($foos); $('#pagination_button a').attr('href', '<%= feed_path + '?page=' + @page %>'); ``` When this ajax call is made the second time, it appears to fail silently. I see the appropriate response in the Firebug console, but `$foos` is not altered and subsequently the `#container` is never appended. My html page only includes a loading indicator, which it successfully replaces on the first call. The second call is triggered from other javascript (Infinite Scroll). If it matters, I have noticed that the first call is made with an automatically generated timestamp parameter. After that I am replacing the target url as you can see on my `#pagination_button a`. How can I debug this in the browser? Update: I used ERB to make `$foos` a dynamic variable ($foos1...$foos2) and noticed that this is also not working. So even though the new `@foos` are visible in the console's response, the first line of my javascript is not being evaluated.