317596 Combo multi select search form

First of all, speaking or at least understanding some Spanish, is not essential for this project but I think it may help you. I need someone to do a simple combo of 3 select fields searching form just like the one in the URL you'll find in the attached file, but instead of using 4 select fields as they do in the example, we'll use just 3 select fields in our form (Province, product/service and subproduct/subservice). We won't use the forth select field used in the example for City/Town. What I want you to do is just to develope a working and operating example and demo which will be later adapted by us and added to our site with final and real content and design. Values for this working demo will be extracted from a fake mysql database which will be provided (structure and data). It is a very simple and basic database: provinces, business product/services and 2 relation tables. Select fields should work as in the example, nested and linked, so when we pick one option, the next fields load possible values depending on our previous selection. Besides, search results are refreshed loading a new url depending on values selected. If you prefer it, you can use dynamic urls to make it simple; we'll change then to static later. When refreshing results I prefer to use a 'real' refresh and reload with url change (just like the example) instead of using ajax related content reloading. Just like the example selects field will not allow multiple selection, users will only be able to pick one option of each field. Results must be paginated, 20 business per page. Design is not required because we will include it in our templates but you must provided at least something viewable, understandable which fits screen. Valid and multibrowser code is a must. Besides, all code must be commented and well explained so we can easily adapt it to our needs. It is very important that you do not copy the example code, you must create you own. Ask before using any js library, framework or environment and if you finally do so, please make sure you do not include more modules, plugins and files than you really need. Thank you very much about your time.