codeigniter属性/过滤系统

I've searched a lot for answers to this question, but I can't find them. Maybe because I'm not searching for the right keywords (because I don't know the right name) or there might be few resources on this subject.

I'd like to build a 'sorting system' in codeigniter for database results. Much like the magento layered navigation or the sorting that's on this site: http://www.wintersporters.nl/skigebieden. On there you can filter ski resorts by price, country, amount of slopes etcetera and the results are automatically updated via AJAX.

another example -> http://www.beslist.nl/products/cddvdrom/cddvdrom_5035278/ where you can sort by date, publisher, genre etcetera.

I'd like the system to be able to pass multiple variables like on wintersporters.nl where you can select multiple countries instead of only one and this way you're able to narrow down your search more and more by selecting multiple attributes until you've found the ski resort that fits you best. So every time you select an option it's preserved in the URL.

How do I achieve something like this? Via the $_GET[] array, with uri's or something totally different? Can anyone point me to a tutorial, snippet of code, explanation or anything related as I can't find out the right way to do this.

I'd be really grateful!

I was also thinking about the component or control which will give me the same functioalities for my web portal but then I developed by own by HTML and Ajax.

In Ajax, you can use

var checkboxValueArray = [];
var val = [];
$('input[name="subcatcheckbox"]:checked').each(function(i){
  val[i] = $(this).val();
  checkboxValueArray.push($('#subcat'+val[i]).text());
});
checkboxValueString = checkboxValueArray.toString();
checkboxValueString = checkboxValueString.replace(/\ /g, "-");
checkboxValueString = checkboxValueString.replace(/\_/g, "-");
checkboxValueString = checkboxValueString.replace(/\,/g, ":");
var checkboxValueNumberString = val.toString();
var checkboxValueNumberString = checkboxValueNumberString.replace(/\,/g, ":");
var pathName ='';
if(checkboxValueNumberString != ''){
  pathName = "events_categories="+checkboxValueString+"&catid="+checkboxValueNumberString;
}
if(pathName != ''){
  window.location.hash = "#!" + pathName;
}
if(pathName == ''){
  window.location.hash = '';
}
getEventsParsedJSON(val);

By this way, I am creating an array on onClick event and then passing to the string to the URL through window.location.hash(ajax method). I developed this in a day. It's easy to develop.