ajax call using prototype not working in rails 3 after migration form rails 2.3

I have been using rails 2.3 earlier and have now migrated to rails 3. I used to make ajax calls like this which worked perfectly fine in rails 2.3

 new Ajax.Request('/user/address', { asynchronous:true, evalScripts:true, parameters:'uid=' + rid });

but after upgrade the same ajax call is no longer working, any help would be appriciated, Thanks.