function GetXmlHttpObject(handler) {
	var objXmlHttp = null;
	if ( navigator.userAgent.indexOf("Opera") >=0 ) {
		alert("This example doesn't work in Opera");
		return;
	}
	if ( navigator.userAgent.indexOf("MSIE") >= 0 ) {
		var strName = "Msxml2.XMLHTTP";
		if ( navigator.appVersion.indexOf("MSIE 5.5") >=0 ) {
			strName = "Microsoft.XMLHTTP";
		}
		try {
			objXmlHttp = new ActiveXObject(strName);
			objXmlHttp.onreadystatechange = handler;
			return objXmlHttp;
		}
		catch(e) {
			alert("Error. Scripting for ActiveX might be disabled");
			return;
		}
	}
	if ( navigator.userAgent.indexOf("Mozilla") >= 0 ) {
		objXmlHttp = new XMLHttpRequest();
		objXmlHttp.onload = handler;
		objXmlHttp.onerror = handler;
		return objXmlHttp;
	}
}

function cityChanged() {
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
		var towns = xmlHttp.responseText;
		eval(towns);
	}
}

function townChanged() {
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
		var shops = xmlHttp.responseText;
		eval(shops);
	}
}

function groupChanged() {
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
		var brands = xmlHttp.responseText;
		eval(brands);
	}
}

function brandChanged() {
	if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete") {
		var brands = xmlHttp.responseText;
		eval(brands);
	}
}

function show_town(val,referer) {
	//clear the drop-down menus:town and sales
	var a,b;
	for(a = document.getElementById("town").options.length - 1; a > 0; a--) {
		document.getElementById("town").options[a] = null;
	}
	for(b=document.getElementById("sales").options.length-1; b > 0; b--) {
		document.getElementById("sales").options[b] = null;
	}
	if ( (val.length > 0) && (referer.length > 0) ) {
		var url = "_bizeulasin_kod?referer="+referer+"&citycode="+val;
		xmlHttp = GetXmlHttpObject(cityChanged);
		xmlHttp.open("GET", url , true);
		xmlHttp.send(null);			
	}
}

function show_brand(val,referer) {
	var i;
	for(i = document.getElementById("brand").options.length - 1; i > 0; i--) {
		document.getElementById("brand").options[i] = null;
	}
	for(i = document.getElementById("model").options.length - 1; i > 0; i--) {
		document.getElementById("model").options[i] = null;
	}
	if ( (val.length > 0) && (referer.length > 0) ) {
		var url = "_bizeulasin_kod?referer="+referer+"&groupcode="+val;
		xmlHttp = GetXmlHttpObject(groupChanged);
		xmlHttp.open("GET", url , true);
		xmlHttp.send(null);
	}
}

function show_model(val,val2,referer) {
	var i;
	var combo_len = document.getElementById("model").options.length;
	for(i=document.getElementById("model").options.length-1; i > 0; i--) {
		document.getElementById("model").options[i]=null;
	}
	if ( (val.length > 0) && (referer.length > 0) ) {
		var url = "_bizeulasin_kod?referer="+referer+"&groupcode="+val+"&brandcode="+val2;
		xmlHttp = GetXmlHttpObject(brandChanged);
		xmlHttp.open("GET", url , true);
		xmlHttp.send(null);
	}
}

function show_shop(val,val2,referer) {
	var i;
	for(i=document.getElementById("sales").options.length-1; i > 0; i--) {
		document.getElementById("sales").options[i]=null;
	}
	if ( (val.length > 0) && (referer.length > 0) ) {
		var url = "_bizeulasin_kod?referer="+referer+"&citycode="+val+"&towncode="+val2;
		xmlHttp = GetXmlHttpObject(townChanged);
		xmlHttp.open("GET", url , true);
		xmlHttp.send(null);
	}
}

function IsNumeric(strString)
//  check for valid numeric strings
{
        var strValidChars = "0123456789.-";
        var strChar;
        var blnResult = true;

        if (strString.length == 0) return false;

        //  test strString consists of valid characters listed above
        for (i = 0; i < strString.length && blnResult == true; i++)
        {
                strChar = strString.charAt(i);

                if (strValidChars.indexOf(strChar) == -1)
                {
                        blnResult = false;
                }
        }
        return blnResult;
}