function goAjax(param,usedfor,area,file) {
        var xmlHttpReq = false;
        if (window.XMLHttpRequest) {
            xmlHttpReq = new XMLHttpRequest();
            if (xmlHttpReq.overrideMimeType) {
                xmlHttpReq.overrideMimeType('text/xml');
            }
        } else if (window.ActiveXObject) {
            try {
                xmlHttpReq = new ActiveXObject("Msxml2.XMLHTTP");
        } catch (e) {
            try {
                xmlHttpReq = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
            }
        }
        if (!xmlHttpReq) {
            alert('ERROR AJAX:( Cannot create an XMLHTTP instance');
            return false;
        }   
		var url=file+"?"+param+'&sid='+Math.random();
        xmlHttpReq.open('GET', url, true);		
		xmlHttpReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
        xmlHttpReq.onreadystatechange = function() { 
            callBackFunction(xmlHttpReq,usedfor,area); 
        };
        xmlHttpReq.send(null);
    }