var obj;
var field_0;
var field_1;
var field_2;
var field_3;
var field_loading;

function fillExtraSelect(host, obj, fk_value, form) {
	this.obj = obj;
	this.field_0 = form.extracountry_id;
	this.field_1 = form.extrastate_id;
	this.field_2 = form.extraregion_id;

	if(document.getElementById('extracity_id')) { this.field_3 = form.extracity_id; }

	resetSelect(obj);

	// check if object exisits.
	if (typeof obj != 'object') return false;

	if (fk_value > 0) {
		form.extracountry_id.disabled=true;
		form.extrastate_id.disabled=true;
		form.extraregion_id.disabled=true;
		if(this.field_3) form.extracity_id.disable=true;
	}

	if (obj.name == "extrastate_id") {
		resetSelect(form.extraregion_id);
		if(this.field_3) resetSelect(form.extracity_id);
		if (fk_value > 0) {
			form.extrastate_id.options[1] = new Option("Loading...", -1);
			form.extrastate_id.options[1].selected=true;
			this.field_loading = form.extrastate_id;
		}
		url = host + '/extra_location.php?country_id=' + fk_value;
		if (fk_value > 0) loadResult(url, '');
	}

	if (obj.name == "extraregion_id") {
		if(this.field_3) resetSelect(form.extracity_id);
		if (fk_value > 0) {
			form.extraregion_id.options[1] = new Option("Loading...", -1);
			form.extraregion_id.options[1].selected=true;
			this.field_loading = form.extraregion_id;
		}
		url = host + '/extra_location.php?state_id=' + fk_value;
		if (fk_value > 0) loadResult(url, '');
	}

	if (obj.name == "extracity_id" && this.field_3) {
		if (fk_value > 0)	 {
			form.extracity_id.options[1] = new Option("Loading...", -1);
			form.extracity_id.options[1].selected=true;
			this.field_loading = form.extracity_id;
		}
		url = host + '/extra_location.php?city_id=' + fk_value;
	}

}

function resetSelect(obj) {
	if(obj) {
        while (obj.options.length>1) {
		    deleteIndex=obj.options.length-1;
		    obj.options[deleteIndex]=null;
	    }
    }
}

function loadXMLDoc(url) {
	// branch for native XMLHttpRequest object
	if (window.XMLHttpRequest) {
		req = new XMLHttpRequest();
		req.onreadystatechange = processReqChange;
		req.open("GET", url, true);
		req.send(null);
	// branch for IE/Windows ActiveX version
	} else if (window.ActiveXObject) {
		req = new ActiveXObject("Microsoft.XMLHTTP");
		if (req) {
			req.onreadystatechange = processReqChange;
			req.open("GET", url, true);
			req.send();
		}
	}
}

function processReqChange() {
	// only if req shows "complete"
	if (req.readyState == 4) {
		// only if "OK"
		if (req.status == 200) {
			// ...processing statements go here
			response  = req.responseXML.documentElement;
			if (response) {
				var result = new Array();
				for (i=0; i < response.getElementsByTagName('id').length; i++) {
					result[i] = {'id': response.getElementsByTagName('id')[i].firstChild.data, 'name': response.getElementsByTagName('name')[i].firstChild.data, 'obj_name': response.getElementsByTagName('obj_name')[i].firstChild.data};
				}
				loadResult('',result);
				unlockLocation();
			}
		} else {
			alert("There was a problem retrieving the XML data:\n" + req.statusText);
		}
	}
}

function loadResult(url, result) {
	if (result != '') {
		// Response mode
		for (i=0; i < result.length; i++) {
			document.getElementById(result[i].obj_name).options[document.getElementById(result[i].obj_name).options.length] = new Option(result[i].name,result[i].id);
		}
	} else if (url != '') {
		// Input mode
		return (loadXMLDoc(url));
	}
}

function unlockLocation() {
	if (this.field_loading) {
		this.field_loading.options[1]=null;
		this.field_loading.options[0].selected=true;
	}
	this.field_0.disabled=false;
	this.field_1.disabled=false;
	this.field_2.disabled=false;
	
	if(this.field_3) this.field_3.disabled=false;
}