jQuery Ajax POST response - knowing which form submitted?

Supposing I had a multi-form page such as:

<form id="A" class="jaxy" ... />
<form id="B" class="jaxy" ... />
<form id="C" class="jaxy" ... />

Then I have some JQuery

$('.jaxy').live('submit', function() {
  $(this).startLoadingSpinner;
  $.post(this.action, $(this).serialize(), $(this).stopLoadingSpinner, "script");
  return false;
});

When a "jaxy" form is submitted there's an Ajax post request and the server might respond with some script like the following:

// The code I wish I had...
// If there was an error with the form it might respond...
$(whichever_form_posted).replaceWith("<form id="B" class="jaxy" .../>")
// or if everything went well it might...
$(whichever_form_posted).empty();
alert("Everything is right with the world! Give yourself a pat on the back.");

The trouble I'm obviously having is knowing which form submitted the post request in the first place. The way is see it I have 3 possible routes:

1. I could potentially send a DOM selector in the POST params? or
2. I could request a HTML response and insert the response data BUT as shown above I might not want to replace so this isn't really an option for me.
3. My preference somehow create a $.fn.function prototype in the response that could be called on the submitting element. This would have to be carefully scoped or unique so that any subsequent for开发者_Python百科m submissions didn't redefine the function.

I'm really struggling to see a way around this and I would appreciate any thoughts on this. It's not necessarily relevant but I'm using this in a RoR environment and the POST request is a .js response to a RESTful controller action. More of a jQuery question that a RoR one I guess.

Kind regards,

Kevin.

---

You've not mentioned what appears to be the most obvious technique: a hidden field.

<input type="hidden" name="form_id" value="foo">

---

Hopefully i understand your problem correctly. What you want to know is which form is actually submitting the data. Here is my code suggestion :

$('.jaxy').live('submit', function() {
  // get the id of the form that makes this request
  var form_id = $(this).attr('id');

  $(this).startLoadingSpinner;

  $.post(this.action, $(this).serialize(), function(data){ 
        alert(form_id); 
    }, "script");

  return false;
});