Question

Back in Rails 2, there was a :condition option in link_to_remote which let you specify some javascript which had to return true or the remote request would not be send. However, in rails 3 it seems like this options has been removed.

What I want to do is have an ajax form, but it needs to undergo validation on the browser before it gets submitted (this is very non-standard validation). Essentially I need to be able to set some conditional javascript expression to prevent the form from being submitted if validation fails – the same as the :condition option from rails 2. Is there any way to achieve this same functionality again in rails 3?

I’m using mootools with the mootools version of rails.js. I looked through the mootools rails.js file and didn’t see anything which looked like it would let me specify some conditional javascript. Am I missing something?

*note: I just looked through the source for the default rails.js file written in prototype. In this file there are there the following lines:

var event = element.fire("ajax:before");
if (event.stopped) return false;

This looks like in the prototype version you can stop the request from being sent by listening to the “ajax:before” event and stopping the event in your listener. However, I can’t find anything like this in the mootools rails.js code, so maybe this is a bug in the mootools rails.js file?

Answer 1

link_to_remote was deleted from Rails 3. It’s a link_to :remote => true now. And if you want to do some js validation, you can use something like this:

<%= link_to "test", '/test', :id => "test-link", :remote => true  %>

and add your validation in the application.js (in my example it’s Prototype. And it’s not a problem to do it with Mootools I guess):

document.observe("dom:loaded", function() {
  $('test-link').observe('click', function(event){
    if your_validation_magic
      event.stop();
  });
});

update:
Mootools has this event too:
https://github.com/kevinvaldek/mootools-ujs/blob/master/Source/rails.js#L131