选择品牌后显示产品[重复]

I'm wondering how do i make it that when i select brand in a drop down menu it will update the other drop down menu with all the prodcuts from that brand

EXAMPLE:

So when i select a brand in the "Make" section it has to put all products from that brand in the "Make" section

http://i48.tinypic.com/rck903.jpg

Thanks if someone helps me.

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If you want do it without POSTBACK, then you have to get the change event of the brand's dropdown and then send an ajax request to server to get the products according to brand id and in success function fill the product dropdown with json output

Example done with jquery:

$('#brand_dd').change(function(){
     $.post(
            'url',
            {'brand_id': $(this).val()},
             function(data){
                //fill your another drop here
             }
}