Javascript prototype.js: How to pass parameter to callback function

Question

Not much knowledge about Javcascript beyond using it for some Dynamic HTML. Now I'm venturing a bit into Ajax ground and have a problem with the following code (borrowed from http://kpumuk.info/php/ajax-enabled-smarty-plugins-part-2-ajax_form/ and edited to fit my needs).

How can I pass the update_id parameter to the obSubmit function?

var SmartyAjax = {

     submit: function(form, update_id, params, callback)
     {
       var myAjax = new Ajax.Request(
       form.action,
       {
         method: form.method,
         parameters: Form.serialize(form.id),
         onComplete: callback || this.onSubmit
       });
     },

     onSubmit: function(originalRequest)
     {
       var results = originalRequest.responseText;
       this.target = $("target2");
       this.target.innerHTML = results;
     }

}

I want to pass update_id to the function onSubmit so that I can assign it as the target. According to the Prototype documentation it gets the Ajax.Response object passed as the first parameter automatically. So, that's what is referenced by originalRequest. I don't see a way to pass update_id to that function as well. How do I do that?

On a related note: I see this "name: function(){}" syntax the first time. What is that? Is that needed because it creates methods of an object? A pointer to a simple explanation would be appreciated.

Thanks very much!

Answer 1

You need to call the function yourself from an anonymous wrapper (unless you want to modify the Prototype source, which I'd strongly suggest you avoid), like this:

 submit: function(form, update_id, params, callback)
 {
   var complete = callback || this.onSubmit;
   var myAjax = new Ajax.Request(
   form.action,
   {
     method: form.method,
     parameters: Form.serialize(form.id),
     onComplete: function(req) { complete.call(this, req, update_id); }
   });
 },

Now your handler will have a second argument, the update_id parameter passed into this function, for example you could do this:

onSubmit: function(originalRequest, update_id) {
  alert(update_id);
}