I am using Rails 2.3.4 at the moment, and as is well known, rails uses Prototype as default javascript library. For most purposes this suits me well.

But what i really like about jQuery is the wealth of plugins readily available.

My solution was not something like jRails, but i use them side by side. This might not be the best solution :)

First of, you have to include the correct javascript files.
Then, at the top of my application.rhtml, i write this:

    var $j = jQuery.noConflict()
    $j(document).ready(function() {
        /* insert some jquery magic here */
        ...
    });

This ensures that i can use the jQuery library nicely alongside the Prototype one. Just replace $ by $j for all jQuery calls.

For most jQuery things this is more than enough. But then I needed form validation, and needed to be able to call some jQuery from inside a link_to_function block. It took me a while to find, but actually (isn’t it always) it is dead-simple.

  def add_document_link(divname, parentdoc )
    link_to_function get_icon('adddocument'), { :title => t('adddocument')} do |page|
      new_doc = Document.new
      new_doc.doc_ident_p = parentdoc.doc_ident
      page.select('.add-items-link').each { |b| b.hide }
      page.insert_html :bottom, divname, :partial => 'documents/add_document', :object => new_doc, :locals => { :divname => "add-items-link"}
      page << "var $j = jQuery.noConflict(); $j(\"form\").validate();"
    end
  end

Easy as pie :) I love rails :)