// change log
// created: 2021-05-09
//populates the drop down dropDownIdToPopulate on selecting a value in drop down selectedItemId
function populateDropDown(selectedItemId, dropDownIdToPopulate, populateVendorCities){
	document.getElementById(dropDownIdToPopulate).style.display = 'none';
	//create the http request checking for mozilla vs ie
	if (window.XMLHttpRequest) {
		httpRequest = new XMLHttpRequest();
		if (httpRequest.overrideMimeType) {
			httpRequest.overrideMimeType('text/xml');
		}
	} else if (window.ActiveXObject) {
		try {
			httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
			} catch (e) {
				try {
					httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
				} catch (e) {}
			}
	}
	//make sure the request was created properly
	if (!httpRequest) {
		//changed to return true so that the form proceeds
		return true;
	}
	selectedItem = document.getElementById(selectedItemId);
	//set our call back function to be called once the info is processed
	httpRequest.onreadystatechange = function() { startPopulatingWithSelect(httpRequest, dropDownIdToPopulate); };
	//query string '&popVenCts' will get cities the vendor have registered or else, get all the cities for the region
	populateCities = '';
	if(populateVendorCities == 1){
	populateCities = '&popVenCts';
	}
	//make the url to be called
	var url = 'getCities.php?rid=' + escape(selectedItem.options[selectedItem.selectedIndex].value) + populateCities;
	try {
		httpRequest.open('GET', url, true);
	} catch(e) {
		//if there is any kind of error opening the request we will return true so that the form submits via normal http
		return true;
	}
	//headers
	httpRequest.setRequestHeader("Connection", "close");
	//send the request
	httpRequest.send(null);
	//set the return to false so that the form is not submitted via html
	return false;
}
//populates the drop down box dropDownIdToPopulate from the xml elements in httpRequest
function startPopulatingWithSelect(httpRequest, dropDownIdToPopulate){
	if (httpRequest.readyState == 4) {
		if (httpRequest.status == 200) {
			//for debugging uncomment the following line
			var xmldoc = httpRequest.responseXML;
			var cities = xmldoc.getElementsByTagName('cities').item(0);
			//get the drop down box element by its id
			mainCitySelect = document.getElementById(dropDownIdToPopulate);
			//clearing the currently listed cities
			cityCount = mainCitySelect.length;
			if (cityCount > 0){
				for (var i=cityCount; i > 0; i--){
					mainCitySelect.options[i] = null;
				}
			}
			//adding the cities to the drop down box
			for(var i=0; i < cities.childNodes.length; i++){
				var cityId = cities.childNodes[i].getAttribute('id');
				var cityName = cities.childNodes[i].firstChild.data;
				//adding the returned cities to the city select box
				mainCitySelect.options[(i + 1)] = new Option(cityName, cityId);
			}
			document.getElementById(dropDownIdToPopulate).style.display = 'block';
        }
	}
}