Help with adding another scroll/effects

[ChrisjChrisj]

I have a Search Form that works successfully, and is using this jQuery plug-in code
(I know it’s not perfect):

$(document).ready(function(){
$("select.ui-select").selectWidget({
change: function(changes) {

var channel_id = changes;
var Parent = $('select[name=sub_category]').parent();

Parent.html('<select  name="sub_category"><option value="All">Sub Category</option></select>');

$.ajax({
type: "POST",
url: "/ajax.php",
data: "channel_id="+channel_id,
dataType: 'json',
statusCode: {
200: function(data) {
for(i = 0; i < data.length; i ++) {
$("select[name='sub_category']").append("<option value='"+data[i]["sub_channel_id"]+"'>"+data[i]["sub_channel_name"]+"</option>");
}
}
}
});
return changes;
},
effect: "slide",
keyControl: true,
speed: 200,
scrollHeight: 120
});
});

I’ve attached a few images for visual aid. SearchForm1.png shows the Search Form.

As you can see in (SearchForm2.png), when the Category is selected it drops down a list and the jquery scroll bar.

After a Category is selected and then the Sub-Category is selected, the list comes down, but no jQuery scroll bar (SearchForm3.png).

I’m wondering if this line:

var Parent = $('select[name=sub_category]').parent();

maybe should be like this instead:

var Parent = $('select[name=channel]').parent();

AND then possibly an additional sub-category function should be added, something like this?:

function ??????????? ()
       {
           $('select[name=sub_category]').selectWidget({
               change       : function (changes) {
                   return changes;
               },
               effect       : "slide",
               keyControl   : true,
               speed        : 200,
               scrollHeight : 200
           });
       }

so, that the sub-category has its own scroll bar/effects.
I believe this script needs the sub-category to have its own:

effect: "slide",
keyControl: true,
speed: 200,
scrollHeight: 120

Any suggestion of how to add a second function for the sub-category (or other suggestions) will be greatly appreciated.

[ChrisjChrisj]

Or, would there be a way to change the code so that just the sub-category gets the scroll/effects and not the (SELECT)Category?