hoptoad report javascript errors

application.js

// in application.js
window.onerror = function(msg, url, line) {
  var location = String(window.location);
  new Ajax.Request('/error/error', {
    method: 'POST',
    parameters: {
      message: msg,
      url: url || location,
      line: line,
      location: location,
      user_agent: navigator.userAgent
    }
  });
}

error_controller.rb

  # in your controller
  def error
    if params[:message]
      msg = "JavaScript Error: '#{params[:message]}'"
      path = ActionController::Routing::Routes.recognize_path(URI.parse(params[:location]).path)
      HoptoadNotifier.notify_or_ignore :error_class => msg,
        :error_message => msg,
        :url => params[:location],
        :controller => path[:controller],
        :action => path[:id] ? path[:id] : 'show', # TODO lame
        :cgi_data => request.env,
        :environment_vars => ENV,
        :parameters => params
    end
    render :nothing => true
  end