function createXMLHttpRequest() {
	
    var ua;
	
    if(window.XMLHttpRequest) {
        try {
            ua = new XMLHttpRequest();
        } catch(e) {
            ua = false;
        }
      } else if(window.ActiveXObject) {
        try {
           ua = new ActiveXObject('Microsoft.XMLHTTP');
        } catch(e) {
           ua = false;
        }
    }
    return ua;
}
	
var req = createXMLHttpRequest();
var currentElement = null;

function executePHPFunc(func,params,callback) {
   req.open('get','functions.php?func='+func+'&'+params);
   req.onreadystatechange = callback;
   req.send(null);
}