function changeCats(topcat, allcats, adv)
{		
	var parent_id = topcat.options[topcat.selectedIndex].value;
	$('cat1').options.length = 0;		

	var url = "/api/categories/jsonChildCategories.php";
	var pars = "catid=" + parent_id;
	
	if(adv == 1)
	{
	    pars = pars + "&adv=1";
	}

	if(allcats == 1)
	{
	    pars = pars + "&allcats=1";
	}

	new Ajax.Request(url,
	  {
		parameters: pars,
	    method:'get',
	    onSuccess: function(transport){
	      var response = transport.responseText || "0";
		  var data = response.evalJSON(true);
		  $('cat1').options.length = 0

	      for(var i=0;i<data.length;i++)
		  {
				var opt = document.createElement('option');
				opt.text = data[i].name;
				opt.value = data[i].id;
				
				$('cat1').options.add(opt);
		  }//end for
		
		}
		
	  });
} //end changeCats