//http://www.captain.at/howto-ajax-form-post-request.php
var http_request = false;
function makePreview(url, parameters, theItem) {
	//alert("makePOSTRequest ITEM: " + theItem);
	http_request = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			// set type accordingly to anticipated content type
			//http_request.overrideMimeType('text/xml');
			http_request.overrideMimeType('text/html');
		}
	}else if(window.ActiveXObject) { // IE
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
			}catch (e){
				try {
					http_request = new ActiveXObject("Microsoft.XMLHTTP");
				} catch (e) {}
		}
	}
	if(!http_request){
		alert('Cannot create XMLHTTP instance');
		return false;
	}

	//http_request.onreadystatechange = alertContents(theItem);
	http_request.onreadystatechange = function(){alertContents(theItem);};
	http_request.open('POST', url, true);
	http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	http_request.setRequestHeader("Content-length", parameters.length);
	http_request.setRequestHeader("Connection", "close");
	http_request.send(parameters);
}

function alertContents(whatItem) {
	//alert("Contents ITEM: " + whatItem);
	if (http_request.readyState == 4) {
		if (http_request.status == 200) {
			result = http_request.responseText;
			document.getElementById(whatItem).innerHTML = result;
		} else {
			alert('There was a problem with the request.');
		}
	}
}

function changeEvent(obj, effectName){
	var poststr = "select_id=" + encodeURI(obj.value);
	document.getElementById(effectName).innerHtml="Loading...";
	makePreview('ajax/register_dates.php', poststr,effectName);
	
}