diff --git a/lib/ajax-chosen.js b/lib/ajax-chosen.js
index 96f0f91..c9e3123 100644
--- a/lib/ajax-chosen.js
+++ b/lib/ajax-chosen.js
@@ -6,11 +6,8 @@
     if (settings == null) {
       settings = {};
     }
-    if (callback == null) {
-      callback = {};
-    }
     if (chosenOptions == null) {
-      chosenOptions = function() {};
+      chosenOptions = {};
     }
     defaultOptions = {
       minTermLength: 3,
@@ -41,7 +38,7 @@
           return false;
         }
         field = $(this);
-        if (!(options.data != null)) {
+        if (options.data == null) {
           options.data = {};
         }
         options.data[options.jsonTermKey] = val;
@@ -51,7 +48,7 @@
         success = options.success;
         options.success = function(data) {
           var items, nbItems, selected_values;
-          if (!(data != null)) {
+          if (data == null) {
             return;
           }
           selected_values = [];
@@ -65,7 +62,7 @@
           select.find('optgroup:empty').each(function() {
             return $(this).remove();
           });
-          items = callback(data);
+          items = callback != null ? callback(data, field) : data;
           nbItems = 0;
           $.each(items, function(i, element) {
             var group, text, value;
@@ -108,8 +105,8 @@
             select.data().chosen.no_results_clear();
             select.data().chosen.no_results(field.val());
           }
-          if (success != null) {
-            success(data);
+          if (settings.success != null) {
+            settings.success(data);
           }
           return field.val(untrimmed_val);
         };
diff --git a/lib/ajax-chosen.min.js b/lib/ajax-chosen.min.js
index 46861d4..108fa0d 100644
--- a/lib/ajax-chosen.min.js
+++ b/lib/ajax-chosen.min.js
@@ -1,17 +1,16 @@
 
 (function($){return $.fn.ajaxChosen=function(settings,callback,chosenOptions){var chosenXhr,defaultOptions,options,select;if(settings==null){settings={};}
-if(callback==null){callback={};}
-if(chosenOptions==null){chosenOptions=function(){};}
+if(chosenOptions==null){chosenOptions={};}
 defaultOptions={minTermLength:3,afterTypeDelay:500,jsonTermKey:"term",keepTypingMsg:"Keep typing...",lookingForMsg:"Looking for"};select=this;chosenXhr=null;options=$.extend({},defaultOptions,$(select).data(),settings);this.chosen(chosenOptions?chosenOptions:{});return this.each(function(){return $(this).next('.chzn-container').find(".search-field > input, .chzn-search > input").bind('keyup',function(){var field,msg,success,untrimmed_val,val;untrimmed_val=$(this).val();val=$.trim($(this).val());msg=val.length<options.minTermLength?options.keepTypingMsg:options.lookingForMsg+(" '"+val+"'");select.next('.chzn-container').find('.no-results').text(msg);if(val===$(this).data('prevVal')){return false;}
 $(this).data('prevVal',val);if(this.timer){clearTimeout(this.timer);}
 if(val.length<options.minTermLength){return false;}
-field=$(this);if(!(options.data!=null)){options.data={};}
+field=$(this);if(options.data==null){options.data={};}
 options.data[options.jsonTermKey]=val;if(options.dataCallback!=null){options.data=options.dataCallback(options.data);}
-success=options.success;options.success=function(data){var items,nbItems,selected_values;if(!(data!=null)){return;}
-selected_values=[];select.find('option').each(function(){if(!$(this).is(":selected")){return $(this).remove();}else{return selected_values.push($(this).val()+"-"+$(this).text());}});select.find('optgroup:empty').each(function(){return $(this).remove();});items=callback(data);nbItems=0;$.each(items,function(i,element){var group,text,value;nbItems++;if(element.group){group=select.find("optgroup[label='"+element.text+"']");if(!group.size()){group=$("<optgroup />");}
+success=options.success;options.success=function(data){var items,nbItems,selected_values;if(data==null){return;}
+selected_values=[];select.find('option').each(function(){if(!$(this).is(":selected")){return $(this).remove();}else{return selected_values.push($(this).val()+"-"+$(this).text());}});select.find('optgroup:empty').each(function(){return $(this).remove();});items=callback!=null?callback(data,field):data;nbItems=0;$.each(items,function(i,element){var group,text,value;nbItems++;if(element.group){group=select.find("optgroup[label='"+element.text+"']");if(!group.size()){group=$("<optgroup />");}
 group.attr('label',element.text).appendTo(select);return $.each(element.items,function(i,element){var text,value;if(typeof element==="string"){value=i;text=element;}else{value=element.value;text=element.text;}
 if($.inArray(value+"-"+text,selected_values)===-1){return $("<option />").attr('value',value).html(text).appendTo(group);}});}else{if(typeof element==="string"){value=i;text=element;}else{value=element.value;text=element.text;}
 if($.inArray(value+"-"+text,selected_values)===-1){return $("<option />").attr('value',value).html(text).appendTo(select);}}});if(nbItems){select.trigger("liszt:updated");}else{select.data().chosen.no_results_clear();select.data().chosen.no_results(field.val());}
-if(success!=null){success(data);}
+if(settings.success!=null){settings.success(data);}
 return field.val(untrimmed_val);};return this.timer=setTimeout(function(){if(chosenXhr){chosenXhr.abort();}
 return chosenXhr=$.ajax(options);},options.afterTypeDelay);});});};})(jQuery);
\ No newline at end of file
diff --git a/src/ajax-chosen.coffee b/src/ajax-chosen.coffee
index 1fcd512..74a4fb6 100644
--- a/src/ajax-chosen.coffee
+++ b/src/ajax-chosen.coffee
@@ -1,6 +1,6 @@
 do ($ = jQuery) ->
 
-  $.fn.ajaxChosen = (settings = {}, callback = {}, chosenOptions = ->) ->
+  $.fn.ajaxChosen = (settings = {}, callback, chosenOptions = {}) ->
     defaultOptions =
       minTermLength: 3
       afterTypeDelay: 500
@@ -10,9 +10,9 @@ do ($ = jQuery) ->
 
     # This will come in handy later.
     select = @
-    
+
     chosenXhr = null
-    
+
     # Merge options with defaults
     options = $.extend {}, defaultOptions, $(select).data(), settings
 
@@ -20,7 +20,7 @@ do ($ = jQuery) ->
     # of using the .chzn-autoselect class to specify input elements
     # we want to use with ajax autocomplete.
     @chosen(if chosenOptions then chosenOptions else {})
-    
+
     @each ->
       # Now that chosen is loaded normally, we can bootstrap it with
       # our ajax autocomplete code.
@@ -29,7 +29,7 @@ do ($ = jQuery) ->
         .bind 'keyup', ->
           # This code will be executed every time the user types a letter
           # into the input form that chosen has created
-          
+
           # Retrieve the current value of the input form
           untrimmed_val = $(@).val()
           val = $.trim $(@).val()
@@ -38,49 +38,49 @@ do ($ = jQuery) ->
           # if they need to keep typing or if we are looking for their data
           msg = if val.length < options.minTermLength then options.keepTypingMsg else options.lookingForMsg + " '#{val}'"
           select.next('.chzn-container').find('.no-results').text(msg)
-          
+
           # If input text has not changed ... do nothing
           return false if val is $(@).data('prevVal')
 
           # Set the current search term so we don't execute the ajax call if
           # the user hits a key that isn't an input letter/number/symbol
           $(@).data('prevVal', val)
-          
+
           # At this point, we have a new term/query ... the old timer
           # is no longer valid.  Clear it.
 
           # We delay searches by a small amount so that we don't flood the
           # server with ajax requests.
           clearTimeout(@timer) if @timer
-          
+
           # Some simple validation so we don't make excess ajax calls. I am
           # assuming you don't want to perform a search with less than 3
           # characters.
           return false if val.length < options.minTermLength
-          
+
           # This is a useful reference for later
           field = $(@)
-          
+
           # Default term key is `term`.  Specify alternative in options.options.jsonTermKey
-          options.data = {} if not options.data?
+          options.data = {} unless options.data?
           options.data[options.jsonTermKey] = val
-          options.data = options.dataCallback(options.data) if options.dataCallback? 
-          
+          options.data = options.dataCallback(options.data) if options.dataCallback?
+
           # If the user provided an ajax success callback, store it so we can
           # call it after our bootstrapping is finished.
           success = options.success
-          
+
           # Create our own callback that will be executed when the ajax call is
           # finished.
           options.success = (data) ->
             # Exit if the data we're given is invalid
-            return if not data?
-            
+            return unless data?
+
             # Go through all of the <option> elements in the <select> and remove
             # ones that have not been selected by the user.  For those selected
             # by the user, add them to a list to filter from the results later.
             selected_values = []
-            select.find('option').each -> 
+            select.find('option').each ->
               if not $(@).is(":selected")
                 $(@).remove()
               else
@@ -88,11 +88,11 @@ do ($ = jQuery) ->
             select.find('optgroup:empty').each ->
               $(@).remove()
 
-                
+
             # Send the ajax results to the user callback so we can get an object of
             # value => text pairs to inject as <option> elements.
-            items = callback data
-            
+            items = if callback? then callback(data, field) else data
+
 
             nbItems = 0
 
@@ -142,7 +142,7 @@ do ($ = jQuery) ->
               select.data().chosen.no_results field.val()
 
             # Finally, call the user supplied callback (if it exists)
-            success(data) if success?
+            settings.success(data) if settings.success?
 
             # For some reason, the contents of the input field get removed once you
             # call trigger above. Often, this can be very annoying (and can make some
@@ -151,19 +151,19 @@ do ($ = jQuery) ->
             field.val(untrimmed_val)
 
             # Because non-ajax Chosen isn't constantly re-building results, when it
-            # DOES rebuild results (during liszt:updated above, it clears the input 
-            # search field before scaling it.  This causes the input field width to be 
-            # at it's minimum, which is about 25px.  
+            # DOES rebuild results (during liszt:updated above, it clears the input
+            # search field before scaling it.  This causes the input field width to be
+            # at it's minimum, which is about 25px.
 
             # The proper way to fix this would be create a new method in chosen for
-            # rebuilding results without clearing the input field.  Or to call 
+            # rebuilding results without clearing the input field.  Or to call
             # Chosen.search_field_scale() after resetting the value above.  This isn't
             # possible with the current state of Chosen.  The quick fix is to simply reset
             # the width of the field after we reset the value of the input text.
             # field.css('width','auto')
-                      
+
           # Execute the ajax call to search for autocomplete data with a timer
-          @timer = setTimeout -> 
+          @timer = setTimeout ->
             chosenXhr.abort() if chosenXhr
             chosenXhr = $.ajax(options)
           , options.afterTypeDelay