function simpleXMLHTTPPost(url, container_id, querystring) {
    // simple ajax requests
    var xmlHttpReq = false;
    var self = this;
    // Mozilla and Safari
    if (window.XMLHttpRequest) {
        self.xmlHttpReq = new XMLHttpRequest();
    }
    // Internet Explorer
    else if (window.ActiveXObject) {
        self.xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
    }
    self.xmlHttpReq.open('POST', url, true);
    self.xmlHttpReq.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    self.xmlHttpReq.onreadystatechange = function() {
        if (self.xmlHttpReq.readyState == 4) {
            updatepage(self.xmlHttpReq.responseText, container_id);
        }
    }
    if (!querystring) {
        querystring = ""
    }
    self.xmlHttpReq.send(querystring);
}



    
function updatepage(html, container_id){
    document.getElementById(container_id).innerHTML = html;
}