function AJAXInteraction(url, callback) {

    var req = init();
    req.onreadystatechange = processRequest;
        
    function init() {
        if(window.ActiveXObject) {  //win ie4,5,6
            try {
                return new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    return new ActiveXObject("Microsoft.XMLHTTP");
                } catch(e2) {
                    return null;
                }
            }
        } else if( window.XMLHttpRequest ) {	//ie¿Ü ¿©·µ..
            return new XMLHttpRequest();
        } else {
            return null;
        }
    }
    
    function processRequest () {
      if (req.readyState == 4) {
        if (req.status == 200) {
          if (callback) callback(req.responseText);
        }
      }
    }

    this.doGet = function() {
      req.open("GET", url, true);
      req.send(null);
    }
    
    this.doPost = function(body) {
      req.open("POST", url, true);
      req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
      req.send(body);
    }
}