function initXMLHTTPRequest() {
  var xRequest=null;
  if(window.XMLHttpRequest){ xRequest = new XMLHttpRequest(); }
  else if(window.ActiveXObject){ xRequest = new ActiveXObject("Microsoft.XMLHTTP"); }
  return xRequest;
}

function onReadyState() {
  var ready = req.readyState;
  if (ready == 4) {    
	data = req.responseText.split(" | ");
	//alert(req.responseText)
	//document.getElementById(data[0]).length = 0;
	outPut(data[0], data[1]);
  }
}  

function outPut(out, data) {
    document.getElementById(out).length = 0;
	if (out == "cat1") { document.getElementById(out).options[0] = new Option("Выберите бренд", ""); }
    else { document.getElementById(out).options[0] = new Option("Выберите модель", ""); }
	out_data = data.split("||");
	for (var i = 0 ; i < (out_data.length - 1) ; i ++) {
	    opt_items = out_data[i].split("::");
	    document.getElementById(out).options[(i + 1)] = new Option(opt_items[1], opt_items[0]);
	}   
}

function full_filtr() {
    block_1 = document.f.cat1.options[document.f.cat1.selectedIndex].text;
    block_2 = document.f.cat2.options[document.f.cat2.selectedIndex].text;
    //alert(document.f.cat2.value)
    //return;
    if (block_1 == "Выберите бренд" || block_2 == "Выберите модель") return;
	else location.href = document.f.cat2.value;
}
    
function doLoad(url) {
    //alert(url);
    req = initXMLHTTPRequest();
    req.onreadystatechange = onReadyState;
    try {
        req.open("GET", url, true);
    }
    catch(e) {
        alert("Извините, данная опция временно не работает")
    }
    req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    req.send(null);
}