Ajax success callback in ruby on rails

Question

Hi want to implement ajax in my ruby on rails tutorials and the controller will return an object on handling the ajax request. I dont know to handle the response in my javascript file. I want to update some div based on object returned in javascript file.

Here is what I have written in my showcomments.js.erb

$('.show_comment').bind('ajax:success', function() {
    $(this).closest('tr')="Something here from the object returned");
});

My link where ajax call is called is via this line of code

 <td><%= link_to 'Show Comment', :action => 'showcomment' , :id =>article, :remote => true ,:class=>'show_comment' %></td>

My controller action where this request is handled is like this

def showcomment
   @article = Article.find(params[:article_id])
   @comment = @article.comments.find(params[:id])
    respond_to do |format|
      format.js{ render :nothing => true }
    end
end

How can this be done?

Answer 1

I just wanted to try and expand on the other answers a little bit.

In rails when you add :remote => true to a link it essentially takes care of the first part of a jquery ajax call. That's why you don't need bind.(ajax:success, function(){ # do stuff here });

This is a typical jquery ajax call

$.ajax({
  url: "test.html",
  type: "POST"
}).done(function() {
  $( this ).addClass( "done" );
});

Rails takes care of the first part, up to the .done callback. So anything in your javascript erb template is put in the callback like this

.done(function() {
  #your showcomments.js.erb file is inserted here
});

To render the showcomments.js.erb template from the controller just do this

def showcomment
  @article = Article.find(params[:article_id])
  @comment = @article.comments.find(params[:id])
  respond_to do |format|
    format.js
  end
end

You don't need anything after format.js because the default rails action at that point is to render a js template with the same name as the action, in this case it's showcomment.js.erb .

Now you know when that link is clicked it will go straight to rendering that showcomment template , and any javascript in there will be run instantly. Rails makes using ajax very simple. I hope that helps.

Answer 2

change showcomment to this:

def showcomment
   @article = Article.find(params[:article_id])
   @comment = @article.comments.find(params[:id])
    respond_to { |format| format.js }
end 

In showcomments.js.erb you can access both objects @article and @comment . A sample use is as below:

$('#yourdiv').html('<%= @article.name %>');

Answer 3

You render nothing when responding to js format. So code in showcomments.js.erb isn't evaluated. Remove { render :nothing => true } in controller and do whatever you want in showcomments.js.erb . BTW you don't need ajax:success event. It is the end of request already.

showcomments.js.erb

$('.show_comment').closest('tr').html("<%= # you may render partial here or whatever %>");