function createRequestObject(){
var request=false;
try{
	request=new XMLHttpRequest();
}catch(trymicrosoft){
	try{
		request=new ActiveXObject("Msxml2.XMLHTTP");
	}catch(othermicrosoft){
		try{
			request=new ActiveXObject("Microsoft.XMLHTTP");
		}catch(failed){
			request=false;
		}
	}
}

if(!request)
alert("Error! Your Browser too OLD! \n Go to get FireFox Now!");

return request;
}
var request=createRequestObject();

///////////clear cache for IE/////////////

function uncache(url){
	var d = new Date();
	var time = d.getTime();
	if (url.indexOf('?') > 0){
		url = url+'&prevent_cache='+time;
	}else{
		url = url+'?prevent_cache='+time;
	}
	return url;
};

///////////Abort lastest request/////////////

function callInProgress(request){
	if(request.readyState != 0 || request.readyState != 4){		//if lastest task is in progress abort it!
			request.abort();
	}
};